Gamma-aminobutyric acid

1. The brain contains two forms of the GABA synthetic enzyme glutamate decarboxylase which differ in molecular size, amino acid sequence, antigenicity, cellular and subcellular location, and interaction with the GAD cofactor pyridoxal phosphate, these forms GAD65 and GAD67 derive from two genes, and their distinctive properties provide a substrate for understanding not only the multiple roles of GABA in the nervous system but also the autoimmune response to GAD in insulin-dependent diabetes mellitus.

   Glutamate decarboxylase 65 / GAD2 → Glutamate decarboxylase 67 / GAD1 source_derived_draftungraded
   Experimental context and source evidence

   evidence_span

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   experimental_model

   Molecular and immunological comparison of the two brain forms of the GABA synthetic enzyme

   exposure

   The two glutamate decarboxylase forms compared for size, sequence, antigenicity, location and cofactor interaction

   limitations

   A characterisation of two gene products. The pancreatic and autoimmune connections are stated as context rather than measured here.

   nutrient_topic

   GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

   organism

   Rat and human genes

   plain_language

   There are two versions of the enzyme that makes this transmitter, and they differ in where they sit and how tightly they hold their cofactor.

   primary_references

   [gb-p2069816] Two genes encode distinct glutamate decarboxylases. (1991). https://pubmed.ncbi.nlm.nih.gov/2069816/ DOI: 10.1016/0896-6273(91)90077-d

   tissue_or_cell_type

   Brain and pancreas

   GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 92–103

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Molecular and immunological comparison of the two brain forms of the GABA synthetic enzyme · source_derived_draft · unverified_draft

   ### gb-two-enzymes-not-one The brain contains two forms of the GABA synthetic enzyme glutamate decarboxylase which differ in molecular size, amino acid sequence, antigenicity, cellular and subcellular location, and interaction with the GAD cofactor pyridoxal phosphate, these forms GAD65 and GAD67 derive from two genes, and their distinctive properties provide a substrate for understanding not only the multiple roles of GABA in the nervous system but also the autoimmune response to GAD in insulin-dependent diabetes mellitus. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: There are two versions of the enzyme that makes this transmitter, and they differ in where they sit and how tightly they hold their cofactor. organism: Rat and human genes tissue_or_cell_type: Brain and pancreas experimental_model: Molecular and immunological comparison of the two brain forms of the GABA synthetic enzyme limitations: A characterisation of two gene products. The pancreatic and autoimmune connections are stated as context rather than measured here. exposure: The two glutamate decarboxylase forms compared for size, sequence, antigenicity, location and cofactor interaction evidence_span: {"source_cache": "artifacts/gaba-research/2069816.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4d940e6978ff77eeee89607aa24fde9036bb58d013063463389a1ca0cb0eb080", "start_char": 0, "end_char": 738, "text_sha256": "4d940e6978ff77eeee89607aa24fde9036bb58d013063463389a1ca0cb0eb080"} [gb-p2069816] Two genes encode distinct glutamate decarboxylases. (1991). https://pubmed.ncbi.nlm.nih.gov/2069816/ DOI: 10.1016/0896-6273(91)90077-d

   Complete structured claim and evidence

2. At least 50% of glutamate decarboxylase is present in brain as apoenzyme, that is enzyme without bound cofactor, which serves as a reservoir of inactive enzyme that can be drawn on when additional GABA synthesis is needed, a substantial majority of the apoenzyme in brain is accounted for by GAD65 although GAD67 also contributes, the interaction of the enzyme with pyridoxal 5-phosphate is a major factor in the short-term regulation of its activity, and the apparent localization of GAD65 in nerve terminals together with the large reserve of apo-GAD65 suggest that GAD65 is specialized to respond to short-term changes in demand for transmitter GABA.

   Apo-glutamate decarboxylase, the form without bound cofactor → Synthesis of GABA from glutamate source_derived_draftungraded
   Experimental context and source evidence

   evidence_span

   {"source_cache": "artifacts/gaba-research/8419527.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "0de2df4de7da887745f27b7c4593a75590b6de3649a2b5b35a1d36980a86b755", "start_char": 0, "end_char": 1425, "text_sha256": "0de2df4de7da887745f27b7c4593a75590b6de3649a2b5b35a1d36980a86b755"}

   experimental_model

   Review of the compartments and short-term regulation of brain GABA synthesis

   exposure

   Glutamate decarboxylase measured as apoenzyme and holoenzyme across brain regions

   limitations

   A review of the enzymology. The apoenzyme fraction is given for total glutamate decarboxylase, with GAD65 accounting for a substantial majority of it rather than being separately quantified.

   nutrient_topic

   GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

   organism

   Rat and human

   plain_language

   Half the enzyme is sitting idle without its cofactor, held in reserve for when more transmitter is suddenly needed.

   primary_references

   [gb-p8419527] Regulation of gamma-aminobutyric acid synthesis in the brain. (1993). https://pubmed.ncbi.nlm.nih.gov/8419527/ DOI: 10.1111/j.1471-4159.1993.tb03165.x

   tissue_or_cell_type

   Brain

   GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 105–116

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Review of the compartments and short-term regulation of brain GABA synthesis · source_derived_draft · unverified_draft

   ### gb-half-the-enzyme-waits At least 50% of glutamate decarboxylase is present in brain as apoenzyme, that is enzyme without bound cofactor, which serves as a reservoir of inactive enzyme that can be drawn on when additional GABA synthesis is needed, a substantial majority of the apoenzyme in brain is accounted for by GAD65 although GAD67 also contributes, the interaction of the enzyme with pyridoxal 5-phosphate is a major factor in the short-term regulation of its activity, and the apparent localization of GAD65 in nerve terminals together with the large reserve of apo-GAD65 suggest that GAD65 is specialized to respond to short-term changes in demand for transmitter GABA. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Half the enzyme is sitting idle without its cofactor, held in reserve for when more transmitter is suddenly needed. organism: Rat and human tissue_or_cell_type: Brain experimental_model: Review of the compartments and short-term regulation of brain GABA synthesis limitations: A review of the enzymology. The apoenzyme fraction is given for total glutamate decarboxylase, with GAD65 accounting for a substantial majority of it rather than being separately quantified. exposure: Glutamate decarboxylase measured as apoenzyme and holoenzyme across brain regions evidence_span: {"source_cache": "artifacts/gaba-research/8419527.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "0de2df4de7da887745f27b7c4593a75590b6de3649a2b5b35a1d36980a86b755", "start_char": 0, "end_char": 1425, "text_sha256": "0de2df4de7da887745f27b7c4593a75590b6de3649a2b5b35a1d36980a86b755"} [gb-p8419527] Regulation of gamma-aminobutyric acid synthesis in the brain. (1993). https://pubmed.ncbi.nlm.nih.gov/8419527/ DOI: 10.1111/j.1471-4159.1993.tb03165.x

   Complete structured claim and evidence

3. Children with pyridoxine-dependent seizures have mutations in the ALDH7A1 gene which encodes antiquitin, these mutations abolish the activity of antiquitin as a delta-1-piperideine-6-carboxylate to alpha-aminoadipic semialdehyde dehydrogenase, the accumulating delta-1-piperideine-6-carboxylate inactivates pyridoxal 5-phosphate by forming a Knoevenagel condensation product, and measurement of urinary alpha-aminoadipic semialdehyde provides a simple way of confirming the diagnosis.

   Delta-1-piperideine-6-carboxylate → PLP source_derived_draftungraded
   Experimental context and source evidence

   availability_state

   machinery_impairment Imported condition classification; unverified.

   evidence_span

   {"source_cache": "artifacts/gaba-research/16491085.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "da61b07cc71e16803fe09321738c7a6c8d2cbac0dff2b189b9f2586ce5950bfa", "start_char": 0, "end_char": 550, "text_sha256": "da61b07cc71e16803fe09321738c7a6c8d2cbac0dff2b189b9f2586ce5950bfa"}

   experimental_model

   Gene analysis and metabolite measurement in children with pyridoxine-dependent seizures

   exposure

   Naturally occurring ALDH7A1 mutations abolishing antiquitin dehydrogenase activity

   limitations

   Human genetics with a defined biochemical consequence. It establishes the chemistry of the cofactor loss; it does not measure brain GABA in the affected children.

   nutrient_topic

   GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

   organism

   Human

   plain_language

   A metabolite that piles up when one enzyme is missing chemically destroys the cofactor a different enzyme needs.

   primary_references

   [gb-p16491085] Mutations in antiquitin in individuals with pyridoxine-dependent seizures. (2006). https://pubmed.ncbi.nlm.nih.gov/16491085/ DOI: 10.1038/nm1366

   tissue_or_cell_type

   Whole body

   trigger_kind

   machinery_impairment Imported condition classification; unverified.

   GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 118–129

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Gene analysis and metabolite measurement in children with pyridoxine-dependent seizures · source_derived_draft · unverified_draft

   ### gb-a-metabolite-destroys-the-cofactor Children with pyridoxine-dependent seizures have mutations in the ALDH7A1 gene which encodes antiquitin, these mutations abolish the activity of antiquitin as a delta-1-piperideine-6-carboxylate to alpha-aminoadipic semialdehyde dehydrogenase, the accumulating delta-1-piperideine-6-carboxylate inactivates pyridoxal 5-phosphate by forming a Knoevenagel condensation product, and measurement of urinary alpha-aminoadipic semialdehyde provides a simple way of confirming the diagnosis. Condition category: machinery_impairment nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: A metabolite that piles up when one enzyme is missing chemically destroys the cofactor a different enzyme needs. organism: Human tissue_or_cell_type: Whole body experimental_model: Gene analysis and metabolite measurement in children with pyridoxine-dependent seizures limitations: Human genetics with a defined biochemical consequence. It establishes the chemistry of the cofactor loss; it does not measure brain GABA in the affected children. exposure: Naturally occurring ALDH7A1 mutations abolishing antiquitin dehydrogenase activity evidence_span: {"source_cache": "artifacts/gaba-research/16491085.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "da61b07cc71e16803fe09321738c7a6c8d2cbac0dff2b189b9f2586ce5950bfa", "start_char": 0, "end_char": 550, "text_sha256": "da61b07cc71e16803fe09321738c7a6c8d2cbac0dff2b189b9f2586ce5950bfa"} [gb-p16491085] Mutations in antiquitin in individuals with pyridoxine-dependent seizures. (2006). https://pubmed.ncbi.nlm.nih.gov/16491085/ DOI: 10.1038/nm1366

   Complete structured claim and evidence

4. Hypophosphatasia is a rare inherited disorder of bone and mineral metabolism caused by loss-of-function mutations in the ALPL gene, characterized by defective bone and tooth mineralisation associated with low serum and bone alkaline phosphatase activity, severe forms may present with neurological problems such as seizures, hypotonia and irritability, and here an infantile hypophosphatasia patient presented with pyridoxine-responsive seizures and a novel homozygous mutation in the ALPL gene was detected, with a limited number of such patients in the literature.

   Tissue-nonspecific alkaline phosphatase ALPL / TNAP → Pyridoxine-responsive seizures in infantile hypophosphatasia source_derived_draftungraded
   Experimental context and source evidence

   availability_state

   machinery_impairment Imported condition classification; unverified.

   evidence_span

   {"source_cache": "artifacts/gaba-research/27086862.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "cb18a717a009e567b4480c6826b39f15109745dbb646c752ad66376b6b107854", "start_char": 0, "end_char": 1299, "text_sha256": "cb18a717a009e567b4480c6826b39f15109745dbb646c752ad66376b6b107854"}

   experimental_model

   Case report of an infant with a novel homozygous ALPL mutation

   exposure

   Loss-of-function ALPL mutation with pyridoxine-responsive seizures

   limitations

   A single case report. It shows the association in one patient and cannot establish how often it occurs or the mechanism by which the cofactor becomes unavailable.

   nutrient_topic

   GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

   organism

   Human

   plain_language

   A child whose alkaline phosphatase does not work had seizures that only pyridoxine controlled.

   primary_references

   [gb-p27086862] Pyridoxine-Responsive Seizures in Infantile Hypophosphatasia and a Novel Homozygous Mutation in ALPL Gene. (2016). https://pubmed.ncbi.nlm.nih.gov/27086862/ DOI: 10.4274/jcrpe.2798

   tissue_or_cell_type

   Bone and nervous system

   trigger_kind

   machinery_impairment Imported condition classification; unverified.

   GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 131–142

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Case report of an infant with a novel homozygous ALPL mutation · source_derived_draft · unverified_draft

   ### gb-losing-the-phosphatase-costs-the-cofactor Hypophosphatasia is a rare inherited disorder of bone and mineral metabolism caused by loss-of-function mutations in the ALPL gene, characterized by defective bone and tooth mineralisation associated with low serum and bone alkaline phosphatase activity, severe forms may present with neurological problems such as seizures, hypotonia and irritability, and here an infantile hypophosphatasia patient presented with pyridoxine-responsive seizures and a novel homozygous mutation in the ALPL gene was detected, with a limited number of such patients in the literature. Condition category: machinery_impairment nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: A child whose alkaline phosphatase does not work had seizures that only pyridoxine controlled. organism: Human tissue_or_cell_type: Bone and nervous system experimental_model: Case report of an infant with a novel homozygous ALPL mutation limitations: A single case report. It shows the association in one patient and cannot establish how often it occurs or the mechanism by which the cofactor becomes unavailable. exposure: Loss-of-function ALPL mutation with pyridoxine-responsive seizures evidence_span: {"source_cache": "artifacts/gaba-research/27086862.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "cb18a717a009e567b4480c6826b39f15109745dbb646c752ad66376b6b107854", "start_char": 0, "end_char": 1299, "text_sha256": "cb18a717a009e567b4480c6826b39f15109745dbb646c752ad66376b6b107854"} [gb-p27086862] Pyridoxine-Responsive Seizures in Infantile Hypophosphatasia and a Novel Homozygous Mutation in ALPL Gene. (2016). https://pubmed.ncbi.nlm.nih.gov/27086862/ DOI: 10.4274/jcrpe.2798

   Complete structured claim and evidence

5. Only GAD65 acts as a major autoantigen, frequently implicated in type 1 diabetes and other autoimmune diseases, hydrogen-deuterium exchange reveals local dynamics accompanying autoinactivation with the catalytic loop promoting collective motions at the C-terminal domain and pyridoxal-5-phosphate domain interface, in the complex with the autoantibody the heavy chain complementarity-determining regions dominate the interaction with a long CDRH3 bridging the GAD65 dimer, and thus intrinsic dynamics rather than sequence differences within epitopes appear to be responsible for the contrasting autoantigenicities of GAD65 and GAD67.

   Conformational dynamics of GAD65 → Autoantigenicity of GAD65 source_derived_draftungraded
   Experimental context and source evidence

   evidence_span

   {"source_cache": "artifacts/gaba-research/40055307.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "832b0c18514e12230379ef877a5bd017fc67e23d762d3b9f00f5d59dc2f7efe2", "start_char": 0, "end_char": 1448, "text_sha256": "832b0c18514e12230379ef877a5bd017fc67e23d762d3b9f00f5d59dc2f7efe2"}

   experimental_model

   Hydrogen-deuterium exchange mass spectrometry, X-ray crystallography and cryo-electron microscopy of the enzyme with a human autoantibody

   exposure

   Apo and holo forms of GAD65 and the complex with the autoantibody b96.11

   limitations

   Structural and dynamic work on isolated protein. The conclusion about autoantigenicity is an interpretation of dynamics rather than an immunological measurement.

   nutrient_topic

   GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

   organism

   Human protein

   plain_language

   What makes one of the two enzymes the target of an autoimmune attack is how much it moves, not how its surface reads.

   primary_references

   [gb-p40055307] Structure and dynamics of GAD65 in complex with an autoimmune polyendocrine syndrome type 2-associated autoantibody. (2025). https://pubmed.ncbi.nlm.nih.gov/40055307/ DOI: 10.1038/s41467-025-57492-4

   tissue_or_cell_type

   Recombinant enzyme

   GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 144–155

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Hydrogen-deuterium exchange mass spectrometry, X-ray crystallography and cryo-electron microscopy of the enzyme with a human autoantibody · source_derived_draft · unverified_draft

   ### gb-dynamics-not-sequence-make-the-autoantigen Only GAD65 acts as a major autoantigen, frequently implicated in type 1 diabetes and other autoimmune diseases, hydrogen-deuterium exchange reveals local dynamics accompanying autoinactivation with the catalytic loop promoting collective motions at the C-terminal domain and pyridoxal-5-phosphate domain interface, in the complex with the autoantibody the heavy chain complementarity-determining regions dominate the interaction with a long CDRH3 bridging the GAD65 dimer, and thus intrinsic dynamics rather than sequence differences within epitopes appear to be responsible for the contrasting autoantigenicities of GAD65 and GAD67. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: What makes one of the two enzymes the target of an autoimmune attack is how much it moves, not how its surface reads. organism: Human protein tissue_or_cell_type: Recombinant enzyme experimental_model: Hydrogen-deuterium exchange mass spectrometry, X-ray crystallography and cryo-electron microscopy of the enzyme with a human autoantibody limitations: Structural and dynamic work on isolated protein. The conclusion about autoantigenicity is an interpretation of dynamics rather than an immunological measurement. exposure: Apo and holo forms of GAD65 and the complex with the autoantibody b96.11 evidence_span: {"source_cache": "artifacts/gaba-research/40055307.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "832b0c18514e12230379ef877a5bd017fc67e23d762d3b9f00f5d59dc2f7efe2", "start_char": 0, "end_char": 1448, "text_sha256": "832b0c18514e12230379ef877a5bd017fc67e23d762d3b9f00f5d59dc2f7efe2"} [gb-p40055307] Structure and dynamics of GAD65 in complex with an autoimmune polyendocrine syndrome type 2-associated autoantibody. (2025). https://pubmed.ncbi.nlm.nih.gov/40055307/ DOI: 10.1038/s41467-025-57492-4

   Complete structured claim and evidence

6. Of 95 patients in the database for whom age at diagnosis is recorded there are 40 individuals currently aged 18 years or older and only 3 patients were diagnosed after age 18 years, of 25 adults for whom data are available after age 18, 60% have a history of epilepsy with predominant seizure types being generalized tonic-clonic, absence and myoclonic, EEGs showed background slowing or generalized epileptiform discharges in two-thirds of adults, history of psychiatric symptoms was prominent with frequent anxiety, sleep disturbances and obsessive-compulsive disorder, and the illness had a progressive course with fatality at age 63 in the index case.

   Succinic semialdehyde dehydrogenase deficiency → Epilepsy in adults with succinic semialdehyde dehydrogenase deficiency source_derived_draftungraded
   Experimental context and source evidence

   evidence_span

   {"source_cache": "artifacts/gaba-research/26268900.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "23c46d68a8a23c3c561454ff56a07ff6ffa1311207b3fb462b079e21a7f6375c", "start_char": 0, "end_char": 1604, "text_sha256": "23c46d68a8a23c3c561454ff56a07ff6ffa1311207b3fb462b079e21a7f6375c"}

   experimental_model

   Review of a clinical database cohort following identification of a patient diagnosed in the seventh decade

   exposure

   Naturally occurring succinic semialdehyde dehydrogenase deficiency followed into adulthood

   limitations

   A database review around an index case. The abstract reports the adult clinical picture; it does not report the accumulating metabolites, so nothing here rests on what backs up behind the missing enzyme.

   nutrient_topic

   GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

   organism

   Human

   plain_language

   When the enzyme that disposes of GABA is missing, most affected adults have epilepsy and psychiatric illness, and the course gets worse.

   primary_references

   [gb-p26268900] Natural history of succinic semialdehyde dehydrogenase deficiency through adulthood. (2015). https://pubmed.ncbi.nlm.nih.gov/26268900/ DOI: 10.1212/wnl.0000000000001906

   tissue_or_cell_type

   Whole body

   GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 157–168

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Review of a clinical database cohort following identification of a patient diagnosed in the seventh decade · source_derived_draft · unverified_draft

   ### gb-losing-the-shunt-enzyme Of 95 patients in the database for whom age at diagnosis is recorded there are 40 individuals currently aged 18 years or older and only 3 patients were diagnosed after age 18 years, of 25 adults for whom data are available after age 18, 60% have a history of epilepsy with predominant seizure types being generalized tonic-clonic, absence and myoclonic, EEGs showed background slowing or generalized epileptiform discharges in two-thirds of adults, history of psychiatric symptoms was prominent with frequent anxiety, sleep disturbances and obsessive-compulsive disorder, and the illness had a progressive course with fatality at age 63 in the index case. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: When the enzyme that disposes of GABA is missing, most affected adults have epilepsy and psychiatric illness, and the course gets worse. organism: Human tissue_or_cell_type: Whole body experimental_model: Review of a clinical database cohort following identification of a patient diagnosed in the seventh decade limitations: A database review around an index case. The abstract reports the adult clinical picture; it does not report the accumulating metabolites, so nothing here rests on what backs up behind the missing enzyme. exposure: Naturally occurring succinic semialdehyde dehydrogenase deficiency followed into adulthood evidence_span: {"source_cache": "artifacts/gaba-research/26268900.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "23c46d68a8a23c3c561454ff56a07ff6ffa1311207b3fb462b079e21a7f6375c", "start_char": 0, "end_char": 1604, "text_sha256": "23c46d68a8a23c3c561454ff56a07ff6ffa1311207b3fb462b079e21a7f6375c"} [gb-p26268900] Natural history of succinic semialdehyde dehydrogenase deficiency through adulthood. (2015). https://pubmed.ncbi.nlm.nih.gov/26268900/ DOI: 10.1212/wnl.0000000000001906

   Complete structured claim and evidence

7. Out of 88 patients exposed to vigabatrin in infancy, 28 were able to perform formal visual field testing, mild vigabatrin-attributed visual field defect was found in four patients and severe defect in one, median vigabatrin treatment duration for those with normal visual field was 11 months compared to 19 months for those with the defect, optical coherence tomography showed concomitant attenuated retinal nerve fiber layer in three children, and the overall prevalence after exposure in infancy is lower than the 52% which has been reported after exposure in adulthood while the risk increases with longer treatment duration.

   Vigabatrin → Vigabatrin-attributed visual field defect source_derived_draftungraded
   Experimental context and source evidence

   evidence_span

   {"source_cache": "artifacts/gaba-research/34716587.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "30459a805ac23ba0a6f0cb4c9484da96a968609466a4bb1fc7c41636542ba887", "start_char": 0, "end_char": 1403, "text_sha256": "30459a805ac23ba0a6f0cb4c9484da96a968609466a4bb1fc7c41636542ba887"}

   experimental_model

   Retrospective population-based perimetry and optical coherence tomography at school age in children exposed in infancy

   exposure

   Vigabatrin given for infantile spasms, with visual fields and retinal nerve fibre layer measured years later

   limitations

   Only 28 of 88 exposed patients could perform formal visual field testing, which limits the prevalence estimate in both directions.

   nutrient_topic

   GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

   organism

   Human

   plain_language

   The drug that raises brain GABA costs some patients their peripheral vision, and the longer they take it the likelier that is.

   primary_references

   [gb-p34716587] Visual field defects after vigabatrin treatment during infancy: retrospective population-based study. (2022). https://pubmed.ncbi.nlm.nih.gov/34716587/ DOI: 10.1111/dmcn.15099

   tissue_or_cell_type

   Retina

   GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 170–181

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Retrospective population-based perimetry and optical coherence tomography at school age in children exposed in infancy · source_derived_draft · unverified_draft

   ### gb-duration-drives-the-field-loss Out of 88 patients exposed to vigabatrin in infancy, 28 were able to perform formal visual field testing, mild vigabatrin-attributed visual field defect was found in four patients and severe defect in one, median vigabatrin treatment duration for those with normal visual field was 11 months compared to 19 months for those with the defect, optical coherence tomography showed concomitant attenuated retinal nerve fiber layer in three children, and the overall prevalence after exposure in infancy is lower than the 52% which has been reported after exposure in adulthood while the risk increases with longer treatment duration. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The drug that raises brain GABA costs some patients their peripheral vision, and the longer they take it the likelier that is. organism: Human tissue_or_cell_type: Retina experimental_model: Retrospective population-based perimetry and optical coherence tomography at school age in children exposed in infancy limitations: Only 28 of 88 exposed patients could perform formal visual field testing, which limits the prevalence estimate in both directions. exposure: Vigabatrin given for infantile spasms, with visual fields and retinal nerve fibre layer measured years later evidence_span: {"source_cache": "artifacts/gaba-research/34716587.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "30459a805ac23ba0a6f0cb4c9484da96a968609466a4bb1fc7c41636542ba887", "start_char": 0, "end_char": 1403, "text_sha256": "30459a805ac23ba0a6f0cb4c9484da96a968609466a4bb1fc7c41636542ba887"} [gb-p34716587] Visual field defects after vigabatrin treatment during infancy: retrospective population-based study. (2022). https://pubmed.ncbi.nlm.nih.gov/34716587/ DOI: 10.1111/dmcn.15099

   Complete structured claim and evidence

8. A close relationship between vigabatrin-induced retinal toxicity and light exposure was observed, vigabatrin-treated mice reared in darkness preserved better visual function and retinal architectures as verified by optokinetic tests, optical coherence tomography and electroretinography, the retinal taurine level of vigabatrin-treated mice exposed to light was significantly lower than that of vigabatrin mice reared in darkness, and the vigabatrin-induced morphological and functional impairments could be partially alleviated by taurine treatment.

   Retinal taurine concentration → Retinal function measured by electroretinography and optokinetic testing source_derived_draftungraded
   Experimental context and source evidence

   evidence_span

   {"source_cache": "artifacts/gaba-research/27941319.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "92835398ef34fe87d3c084d1933722427a474b40c88c30ada21a6ede8f4d875a", "start_char": 0, "end_char": 1596, "text_sha256": "92835398ef34fe87d3c084d1933722427a474b40c88c30ada21a6ede8f4d875a"}

   experimental_model

   Electroretinography, optical coherence tomography and optokinetic testing in mice reared in light or darkness

   exposure

   Vigabatrin with and without light exposure, and with taurine supplementation

   limitations

   A mouse study. It identifies two contributing factors and shows partial rescue, not that taurine prevents the human visual field defect.

   nutrient_topic

   GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

   organism

   Mouse

   plain_language

   The retinal damage needed light to happen, went with a fall in retinal taurine, and was partly undone by giving taurine back.

   primary_references

   [gb-p27941319] The Vigabatrin Induced Retinal Toxicity is Associated with Photopic Exposure and Taurine Deficiency: An In Vivo Study. (2016). https://pubmed.ncbi.nlm.nih.gov/27941319/ DOI: 10.1159/000453143

   tissue_or_cell_type

   Retina

   GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 183–194

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Electroretinography, optical coherence tomography and optokinetic testing in mice reared in light or darkness · source_derived_draft · unverified_draft

   ### gb-light-and-taurine-both-matter A close relationship between vigabatrin-induced retinal toxicity and light exposure was observed, vigabatrin-treated mice reared in darkness preserved better visual function and retinal architectures as verified by optokinetic tests, optical coherence tomography and electroretinography, the retinal taurine level of vigabatrin-treated mice exposed to light was significantly lower than that of vigabatrin mice reared in darkness, and the vigabatrin-induced morphological and functional impairments could be partially alleviated by taurine treatment. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The retinal damage needed light to happen, went with a fall in retinal taurine, and was partly undone by giving taurine back. organism: Mouse tissue_or_cell_type: Retina experimental_model: Electroretinography, optical coherence tomography and optokinetic testing in mice reared in light or darkness limitations: A mouse study. It identifies two contributing factors and shows partial rescue, not that taurine prevents the human visual field defect. exposure: Vigabatrin with and without light exposure, and with taurine supplementation evidence_span: {"source_cache": "artifacts/gaba-research/27941319.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "92835398ef34fe87d3c084d1933722427a474b40c88c30ada21a6ede8f4d875a", "start_char": 0, "end_char": 1596, "text_sha256": "92835398ef34fe87d3c084d1933722427a474b40c88c30ada21a6ede8f4d875a"} [gb-p27941319] The Vigabatrin Induced Retinal Toxicity is Associated with Photopic Exposure and Taurine Deficiency: An In Vivo Study. (2016). https://pubmed.ncbi.nlm.nih.gov/27941319/ DOI: 10.1159/000453143

   Complete structured claim and evidence

9. GABA is the main inhibitory transmitter in the adult brain and exerts its fast hyperpolarizing effect through activation of anion-permeant GABA-A receptors, however during early neuronal development GABA-A-receptor-mediated responses are often depolarizing, in pyramidal neurons of the rat hippocampus the ontogenetic change in GABA-A-mediated responses from depolarizing to hyperpolarizing is coupled to a developmental induction of the expression of the neuronal chloride-extruding potassium-chloride co-transporter KCC2, and antisense oligonucleotide inhibition of KCC2 expression produces a marked positive shift in the reversal potential of GABA-A responses in functionally mature hippocampal pyramidal neurons.

   The neuronal potassium-chloride co-transporter KCC2 → Whether a GABA-A response hyperpolarises or depolarises the cell source_derived_draftungraded
   Experimental context and source evidence

   availability_state

   machinery_impairment Imported condition classification; unverified.

   evidence_span

   {"source_cache": "artifacts/gaba-research/9930699.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "2ef63b1f73a7a33ae3fc709c3ace45a585604d86f9fe1bce8c83405d21cdcaa6", "start_char": 0, "end_char": 1181, "text_sha256": "2ef63b1f73a7a33ae3fc709c3ace45a585604d86f9fe1bce8c83405d21cdcaa6"}

   experimental_model

   Developmental comparison of GABA-A responses with antisense inhibition of the transporter

   exposure

   Antisense oligonucleotide inhibition of KCC2 expression in functionally mature neurons

   limitations

   Rat hippocampal neurons. It establishes which transporter sets the gradient; it does not address other cell types.

   nutrient_topic

   GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

   organism

   Rat

   plain_language

   The same receptor flips from exciting to inhibiting as the cell learns to pump chloride out, and knocking the pump down flips it back.

   primary_references

   [gb-p9930699] The K+/Cl- co-transporter KCC2 renders GABA hyperpolarizing during neuronal maturation. (1999). https://pubmed.ncbi.nlm.nih.gov/9930699/ DOI: 10.1038/16697

   tissue_or_cell_type

   Hippocampal pyramidal neuron

   trigger_kind

   machinery_impairment Imported condition classification; unverified.

   GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 196–207

   AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Developmental comparison of GABA-A responses with antisense inhibition of the transporter · source_derived_draft · unverified_draft

   ### gb-the-transporter-sets-the-sign GABA is the main inhibitory transmitter in the adult brain and exerts its fast hyperpolarizing effect through activation of anion-permeant GABA-A receptors, however during early neuronal development GABA-A-receptor-mediated responses are often depolarizing, in pyramidal neurons of the rat hippocampus the ontogenetic change in GABA-A-mediated responses from depolarizing to hyperpolarizing is coupled to a developmental induction of the expression of the neuronal chloride-extruding potassium-chloride co-transporter KCC2, and antisense oligonucleotide inhibition of KCC2 expression produces a marked positive shift in the reversal potential of GABA-A responses in functionally mature hippocampal pyramidal neurons. Condition category: machinery_impairment nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The same receptor flips from exciting to inhibiting as the cell learns to pump chloride out, and knocking the pump down flips it back. organism: Rat tissue_or_cell_type: Hippocampal pyramidal neuron experimental_model: Developmental comparison of GABA-A responses with antisense inhibition of the transporter limitations: Rat hippocampal neurons. It establishes which transporter sets the gradient; it does not address other cell types. exposure: Antisense oligonucleotide inhibition of KCC2 expression in functionally mature neurons evidence_span: {"source_cache": "artifacts/gaba-research/9930699.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "2ef63b1f73a7a33ae3fc709c3ace45a585604d86f9fe1bce8c83405d21cdcaa6", "start_char": 0, "end_char": 1181, "text_sha256": "2ef63b1f73a7a33ae3fc709c3ace45a585604d86f9fe1bce8c83405d21cdcaa6"} [gb-p9930699] The K+/Cl- co-transporter KCC2 renders GABA hyperpolarizing during neuronal maturation. (1999). https://pubmed.ncbi.nlm.nih.gov/9930699/ DOI: 10.1038/16697

   Complete structured claim and evidence

10. Following peripheral nerve injury there is a trans-synaptic reduction in the expression of the potassium-chloride exporter KCC2 and consequent disruption of anion homeostasis in neurons of lamina I of the superficial dorsal horn, the resulting shift in the transmembrane anion gradient caused normally inhibitory anionic synaptic currents to be excitatory, substantially driving up the net excitability of lamina I neurons, and local blockade or knock-down of the spinal KCC2 exporter in intact rats markedly reduced the nociceptive threshold, confirming that the disruption of anion homeostasis was sufficient to cause neuropathic pain.

    Peripheral nerve injury → The neuronal potassium-chloride co-transporter KCC2 source_derived_draftungraded
    Experimental context and source evidence

    availability_state

    machinery_impairment Imported condition classification; unverified.

    evidence_span

    {"source_cache": "artifacts/gaba-research/12931188.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "f465ce014f8ada8e6018e23f0009197609a343241b8d0926b34ed186ce345fa4", "start_char": 0, "end_char": 1073, "text_sha256": "f465ce014f8ada8e6018e23f0009197609a343241b8d0926b34ed186ce345fa4"}

    experimental_model

    Recordings from lamina I neurons after peripheral nerve injury, with spinal blockade and knockdown in intact animals

    exposure

    Peripheral nerve injury, and local blockade or knock-down of spinal KCC2 in intact rats

    limitations

    The knockdown in intact animals is what makes this causal rather than correlative: reproducing the gradient change alone reproduced the pain phenotype.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Rat

    plain_language

    After nerve injury the inhibitory synapses in the pain pathway start doing the opposite of inhibiting.

    primary_references

    [gb-p12931188] Trans-synaptic shift in anion gradient in spinal lamina I neurons as a mechanism of neuropathic pain. (2003). https://pubmed.ncbi.nlm.nih.gov/12931188/ DOI: 10.1038/nature01868

    tissue_or_cell_type

    Spinal lamina I dorsal horn neuron

    trigger_kind

    machinery_impairment Imported condition classification; unverified.

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 209–220

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recordings from lamina I neurons after peripheral nerve injury, with spinal blockade and knockdown in intact animals · source_derived_draft · unverified_draft

    ### gb-inhibition-becomes-excitation Following peripheral nerve injury there is a trans-synaptic reduction in the expression of the potassium-chloride exporter KCC2 and consequent disruption of anion homeostasis in neurons of lamina I of the superficial dorsal horn, the resulting shift in the transmembrane anion gradient caused normally inhibitory anionic synaptic currents to be excitatory, substantially driving up the net excitability of lamina I neurons, and local blockade or knock-down of the spinal KCC2 exporter in intact rats markedly reduced the nociceptive threshold, confirming that the disruption of anion homeostasis was sufficient to cause neuropathic pain. Condition category: machinery_impairment nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: After nerve injury the inhibitory synapses in the pain pathway start doing the opposite of inhibiting. organism: Rat tissue_or_cell_type: Spinal lamina I dorsal horn neuron experimental_model: Recordings from lamina I neurons after peripheral nerve injury, with spinal blockade and knockdown in intact animals limitations: The knockdown in intact animals is what makes this causal rather than correlative: reproducing the gradient change alone reproduced the pain phenotype. exposure: Peripheral nerve injury, and local blockade or knock-down of spinal KCC2 in intact rats evidence_span: {"source_cache": "artifacts/gaba-research/12931188.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "f465ce014f8ada8e6018e23f0009197609a343241b8d0926b34ed186ce345fa4", "start_char": 0, "end_char": 1073, "text_sha256": "f465ce014f8ada8e6018e23f0009197609a343241b8d0926b34ed186ce345fa4"} [gb-p12931188] Trans-synaptic shift in anion gradient in spinal lamina I neurons as a mechanism of neuropathic pain. (2003). https://pubmed.ncbi.nlm.nih.gov/12931188/ DOI: 10.1038/nature01868

    Complete structured claim and evidence

11. ATP-stimulated microglia cause a depolarizing shift in the anion reversal potential in spinal lamina I neurons which inverts the polarity of currents activated by GABA as occurs after peripheral nerve injury, applying brain-derived neurotrophic factor mimics the alteration, blocking signalling between BDNF and the receptor TrkB reverses the allodynia and the shift that follows both nerve injury and administration of ATP-stimulated microglia, and preventing BDNF release from microglia by pretreating them with interfering RNA before ATP stimulation also inhibits the effects on the withdrawal threshold.

    Brain-derived neurotrophic factor → The reversal potential of anion currents source_derived_draftungraded
    Experimental context and source evidence

    availability_state

    machinery_impairment Imported condition classification; unverified.

    evidence_span

    {"source_cache": "artifacts/gaba-research/16355225.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "75e8e0a216ad3cbd68087f650d263b38fe34b73a6b3b253b929b2af26434e001", "start_char": 0, "end_char": 1571, "text_sha256": "75e8e0a216ad3cbd68087f650d263b38fe34b73a6b3b253b929b2af26434e001"}

    experimental_model

    Recordings from lamina I neurons exposed to ATP-stimulated microglia, with BDNF blockade and interfering RNA

    exposure

    ATP-stimulated microglia, applied BDNF, BDNF-TrkB blockade, and interfering RNA against BDNF in microglia

    limitations

    Each link in the chain is cut separately, which is what makes the assignment to BDNF strong. It remains a rodent model of one pain state.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Rat

    plain_language

    An immune cell in the spinal cord releases a growth factor that turns the brake into an accelerator.

    primary_references

    [gb-p16355225] BDNF from microglia causes the shift in neuronal anion gradient underlying neuropathic pain. (2005). https://pubmed.ncbi.nlm.nih.gov/16355225/ DOI: 10.1038/nature04223

    tissue_or_cell_type

    Spinal lamina I dorsal horn neuron and microglia

    trigger_kind

    machinery_impairment Imported condition classification; unverified.

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 222–233

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recordings from lamina I neurons exposed to ATP-stimulated microglia, with BDNF blockade and interfering RNA · source_derived_draft · unverified_draft

    ### gb-microglia-invert-the-current ATP-stimulated microglia cause a depolarizing shift in the anion reversal potential in spinal lamina I neurons which inverts the polarity of currents activated by GABA as occurs after peripheral nerve injury, applying brain-derived neurotrophic factor mimics the alteration, blocking signalling between BDNF and the receptor TrkB reverses the allodynia and the shift that follows both nerve injury and administration of ATP-stimulated microglia, and preventing BDNF release from microglia by pretreating them with interfering RNA before ATP stimulation also inhibits the effects on the withdrawal threshold. Condition category: machinery_impairment nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: An immune cell in the spinal cord releases a growth factor that turns the brake into an accelerator. organism: Rat tissue_or_cell_type: Spinal lamina I dorsal horn neuron and microglia experimental_model: Recordings from lamina I neurons exposed to ATP-stimulated microglia, with BDNF blockade and interfering RNA limitations: Each link in the chain is cut separately, which is what makes the assignment to BDNF strong. It remains a rodent model of one pain state. exposure: ATP-stimulated microglia, applied BDNF, BDNF-TrkB blockade, and interfering RNA against BDNF in microglia evidence_span: {"source_cache": "artifacts/gaba-research/16355225.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "75e8e0a216ad3cbd68087f650d263b38fe34b73a6b3b253b929b2af26434e001", "start_char": 0, "end_char": 1571, "text_sha256": "75e8e0a216ad3cbd68087f650d263b38fe34b73a6b3b253b929b2af26434e001"} [gb-p16355225] BDNF from microglia causes the shift in neuronal anion gradient underlying neuropathic pain. (2005). https://pubmed.ncbi.nlm.nih.gov/16355225/ DOI: 10.1038/nature04223

    Complete structured claim and evidence

12. By introducing a histidine-to-arginine point mutation at position 101 of the murine alpha1-subunit gene, alpha1-type GABA-A receptors which are mainly expressed in cortical areas and thalamus are rendered insensitive to allosteric modulation by benzodiazepine-site ligands whilst regulation by the physiological neurotransmitter GABA is preserved, alpha1(H101R) mice failed to show the sedative, amnesic and partly the anticonvulsant action of diazepam, in contrast the anxiolytic-like, myorelaxant, motor-impairing and ethanol-potentiating effects were fully retained and are attributed to the nonmutated receptors found in the limbic system, in monoaminergic neurons and in motoneurons.

    The alpha-1 subunit histidine-101-to-arginine point mutation → Sedation source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/10548105.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "73f8793d4606905cc7330c56b3345629a48e652c824f1dfecc9c4670c3c9b74b", "start_char": 0, "end_char": 1270, "text_sha256": "73f8793d4606905cc7330c56b3345629a48e652c824f1dfecc9c4670c3c9b74b"}

    experimental_model

    Knock-in mice carrying a point mutation that removes benzodiazepine sensitivity from one subunit

    exposure

    A histidine-to-arginine point mutation at position 101 of the alpha-1 subunit, with diazepam

    limitations

    A single-residue knock-in that separates drug actions by subunit. GABA regulation of the mutated receptor is preserved, which is what makes the dissociation clean.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    Change one amino acid and the same drug stops sedating the animal while still calming it, because different effects run through different subunits.

    primary_references

    [gb-p10548105] Benzodiazepine actions mediated by specific gamma-aminobutyric acid(A) receptor subtypes. (1999). https://pubmed.ncbi.nlm.nih.gov/10548105/ DOI: 10.1038/44579

    tissue_or_cell_type

    Cortex, thalamus and limbic system

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 235–246

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Knock-in mice carrying a point mutation that removes benzodiazepine sensitivity from one subunit · source_derived_draft · unverified_draft

    ### gb-one-subunit-carries-the-sedation By introducing a histidine-to-arginine point mutation at position 101 of the murine alpha1-subunit gene, alpha1-type GABA-A receptors which are mainly expressed in cortical areas and thalamus are rendered insensitive to allosteric modulation by benzodiazepine-site ligands whilst regulation by the physiological neurotransmitter GABA is preserved, alpha1(H101R) mice failed to show the sedative, amnesic and partly the anticonvulsant action of diazepam, in contrast the anxiolytic-like, myorelaxant, motor-impairing and ethanol-potentiating effects were fully retained and are attributed to the nonmutated receptors found in the limbic system, in monoaminergic neurons and in motoneurons. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Change one amino acid and the same drug stops sedating the animal while still calming it, because different effects run through different subunits. organism: Mouse tissue_or_cell_type: Cortex, thalamus and limbic system experimental_model: Knock-in mice carrying a point mutation that removes benzodiazepine sensitivity from one subunit limitations: A single-residue knock-in that separates drug actions by subunit. GABA regulation of the mutated receptor is preserved, which is what makes the dissociation clean. exposure: A histidine-to-arginine point mutation at position 101 of the alpha-1 subunit, with diazepam evidence_span: {"source_cache": "artifacts/gaba-research/10548105.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "73f8793d4606905cc7330c56b3345629a48e652c824f1dfecc9c4670c3c9b74b", "start_char": 0, "end_char": 1270, "text_sha256": "73f8793d4606905cc7330c56b3345629a48e652c824f1dfecc9c4670c3c9b74b"} [gb-p10548105] Benzodiazepine actions mediated by specific gamma-aminobutyric acid(A) receptor subtypes. (1999). https://pubmed.ncbi.nlm.nih.gov/10548105/ DOI: 10.1038/44579

    Complete structured claim and evidence

13. The GABA-A receptor and hypnotic potencies of etomidate and the etomidate analogs ranged by 91-fold and 53-fold respectively, these potency measurements were significantly correlated with r = 0.72, but neither measurement correlated with drug hydrophobicity with r = 0.019 and 0.005 respectively, statistically significant and predictive comparative molecular field analysis models were generated, and a pharmacophore model was built revealing both the structural elements associated with high potency and the interactions that these elements make with the etomidate-binding site.

    The etomidate-binding site of the GABA-A receptor → Etomidate source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/26691905.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1143ce4efd922ff301b6a1ca54f0a84b8ffe08bf53946b8fcee1f3ad17a8b7eb", "start_char": 0, "end_char": 1844, "text_sha256": "1143ce4efd922ff301b6a1ca54f0a84b8ffe08bf53946b8fcee1f3ad17a8b7eb"}

    experimental_model

    Voltage clamp electrophysiology of a sensitising channel mutant with a loss of righting reflex assay and comparative molecular field analysis

    exposure

    A series of etomidate analogs spanning a 91-fold range of receptor potency

    limitations

    Recombinant receptors carrying a mutation that enhances anaesthetic sensitivity, paired with an animal endpoint. The correlation is across analogs rather than within one drug.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Rat and recombinant receptor

    plain_language

    How well these anaesthetics work tracks their exact shape at a binding site and not at all how greasy they are.

    primary_references

    [gb-p26691905] γ-Aminobutyric Acid Type A Receptor Modulation by Etomidate Analogs. (2016). https://pubmed.ncbi.nlm.nih.gov/26691905/ DOI: 10.1097/aln.0000000000000992

    tissue_or_cell_type

    Recombinant alpha1beta3gamma2 receptors and whole animals

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 248–259

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Voltage clamp electrophysiology of a sensitising channel mutant with a loss of righting reflex assay and comparative molecular field analysis · source_derived_draft · unverified_draft

    ### gb-potency-is-structural-not-greasy The GABA-A receptor and hypnotic potencies of etomidate and the etomidate analogs ranged by 91-fold and 53-fold respectively, these potency measurements were significantly correlated with r = 0.72, but neither measurement correlated with drug hydrophobicity with r = 0.019 and 0.005 respectively, statistically significant and predictive comparative molecular field analysis models were generated, and a pharmacophore model was built revealing both the structural elements associated with high potency and the interactions that these elements make with the etomidate-binding site. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: How well these anaesthetics work tracks their exact shape at a binding site and not at all how greasy they are. organism: Rat and recombinant receptor tissue_or_cell_type: Recombinant alpha1beta3gamma2 receptors and whole animals experimental_model: Voltage clamp electrophysiology of a sensitising channel mutant with a loss of righting reflex assay and comparative molecular field analysis limitations: Recombinant receptors carrying a mutation that enhances anaesthetic sensitivity, paired with an animal endpoint. The correlation is across analogs rather than within one drug. exposure: A series of etomidate analogs spanning a 91-fold range of receptor potency evidence_span: {"source_cache": "artifacts/gaba-research/26691905.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1143ce4efd922ff301b6a1ca54f0a84b8ffe08bf53946b8fcee1f3ad17a8b7eb", "start_char": 0, "end_char": 1844, "text_sha256": "1143ce4efd922ff301b6a1ca54f0a84b8ffe08bf53946b8fcee1f3ad17a8b7eb"} [gb-p26691905] γ-Aminobutyric Acid Type A Receptor Modulation by Etomidate Analogs. (2016). https://pubmed.ncbi.nlm.nih.gov/26691905/ DOI: 10.1097/aln.0000000000000992

    Complete structured claim and evidence

14. Zinc is an abundant trace metal in the hippocampus nerve terminals and blocked the GABA-evoked and ganaxolone-potentiated GABA-gated chloride currents in dentate gyrus granule cells and CA1 pyramidal cells in a concentration-dependent fashion similar to competitive GABA-A receptor antagonists, zinc completely blocked ganaxolone potentiation of extrasynaptic tonic currents but not synaptic phasic currents, systemic ganaxolone produced dose-dependent suppression of behavioral and electrographic seizures in fully-kindled mice with complete protection at 10 mg/kg, however the antiseizure effects were significantly prevented by intrahippocampal zinc with a median effective dose of 150 micromolar, and the response was reversible.

    Zinc(II) ion → Extrasynaptic GABA-A receptors mediating tonic current source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/30471294.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "657923c781b7e3a3309235bce60303fde53f18d7a830cde050b268269f02747a", "start_char": 0, "end_char": 1814, "text_sha256": "657923c781b7e3a3309235bce60303fde53f18d7a830cde050b268269f02747a"}

    experimental_model

    Recordings of tonic and phasic currents in dissociated hippocampal neurons and slices, with a kindled seizure model

    exposure

    Zinc with the synthetic neurosteroid ganaxolone, applied to neurons and intrahippocampally in fully kindled mice

    limitations

    The separation of tonic from phasic current is what makes the subunit assignment work. Zinc was given intrahippocampally at a defined dose rather than altered nutritionally.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    Zinc shuts down the steroid-sensitive receptors that sit outside synapses while leaving the ones inside synapses working.

    primary_references

    [gb-p30471294] Zinc reduces antiseizure activity of neurosteroids by selective blockade of extrasynaptic GABA-A receptor-mediated tonic inhibition in the hippocampus. (2019). https://pubmed.ncbi.nlm.nih.gov/30471294/ DOI: 10.1016/j.neuropharm.2018.11.031

    tissue_or_cell_type

    Dentate gyrus granule cells and CA1 pyramidal cells

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 261–272

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Recordings of tonic and phasic currents in dissociated hippocampal neurons and slices, with a kindled seizure model · source_derived_draft · unverified_draft

    ### gb-zinc-blocks-only-the-tonic-receptors Zinc is an abundant trace metal in the hippocampus nerve terminals and blocked the GABA-evoked and ganaxolone-potentiated GABA-gated chloride currents in dentate gyrus granule cells and CA1 pyramidal cells in a concentration-dependent fashion similar to competitive GABA-A receptor antagonists, zinc completely blocked ganaxolone potentiation of extrasynaptic tonic currents but not synaptic phasic currents, systemic ganaxolone produced dose-dependent suppression of behavioral and electrographic seizures in fully-kindled mice with complete protection at 10 mg/kg, however the antiseizure effects were significantly prevented by intrahippocampal zinc with a median effective dose of 150 micromolar, and the response was reversible. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Zinc shuts down the steroid-sensitive receptors that sit outside synapses while leaving the ones inside synapses working. organism: Mouse tissue_or_cell_type: Dentate gyrus granule cells and CA1 pyramidal cells experimental_model: Recordings of tonic and phasic currents in dissociated hippocampal neurons and slices, with a kindled seizure model limitations: The separation of tonic from phasic current is what makes the subunit assignment work. Zinc was given intrahippocampally at a defined dose rather than altered nutritionally. exposure: Zinc with the synthetic neurosteroid ganaxolone, applied to neurons and intrahippocampally in fully kindled mice evidence_span: {"source_cache": "artifacts/gaba-research/30471294.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "657923c781b7e3a3309235bce60303fde53f18d7a830cde050b268269f02747a", "start_char": 0, "end_char": 1814, "text_sha256": "657923c781b7e3a3309235bce60303fde53f18d7a830cde050b268269f02747a"} [gb-p30471294] Zinc reduces antiseizure activity of neurosteroids by selective blockade of extrasynaptic GABA-A receptor-mediated tonic inhibition in the hippocampus. (2019). https://pubmed.ncbi.nlm.nih.gov/30471294/ DOI: 10.1016/j.neuropharm.2018.11.031

    Complete structured claim and evidence

15. Cells heterologously expressing the cloned DNA encoding the GABA-B R1 protein exhibit high-affinity antagonist-binding sites but produce little of the functional activity expected from studies of endogenous GABA-B receptors in the brain, neither GABA-B R1 nor GABA-B R2 when expressed individually activates GIRK-type potassium channels, however the combination of the two confers robust stimulation of channel activity, both genes are co-expressed in individual neurons and both proteins co-localize in transfected cells, and immunoprecipitation indicates that the two polypeptides associate with each other probably as heterodimers.

    The GABA-B receptor heterodimer → G-protein-gated inwardly rectifying potassium (GIRK) channels source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/9872315.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "c6687fd9eb8b7ebcc0496a2385b0201b02662a5fe8da87a0089650a150f00613", "start_char": 0, "end_char": 1473, "text_sha256": "c6687fd9eb8b7ebcc0496a2385b0201b02662a5fe8da87a0089650a150f00613"}

    experimental_model

    Heterologous expression and immunoprecipitation of two GABA-B polypeptides with potassium channel readout

    exposure

    GABA-B R1 and R2 expressed alone and together, with GIRK-type potassium channel activity as the readout

    limitations

    Heterologous expression. The functional claim rests on channel activation in transfected cells rather than in native tissue.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Rat and human genes

    plain_language

    Two proteins that each do almost nothing on their own make a working receptor only when put together.

    primary_references

    [gb-p9872315] GABA(B) receptors function as a heteromeric assembly of the subunits GABA(B)R1 and GABA(B)R2. (1998). https://pubmed.ncbi.nlm.nih.gov/9872315/ DOI: 10.1038/25348

    tissue_or_cell_type

    Transfected cells and neurons

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 274–285

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Heterologous expression and immunoprecipitation of two GABA-B polypeptides with potassium channel readout · source_derived_draft · unverified_draft

    ### gb-neither-half-works-alone Cells heterologously expressing the cloned DNA encoding the GABA-B R1 protein exhibit high-affinity antagonist-binding sites but produce little of the functional activity expected from studies of endogenous GABA-B receptors in the brain, neither GABA-B R1 nor GABA-B R2 when expressed individually activates GIRK-type potassium channels, however the combination of the two confers robust stimulation of channel activity, both genes are co-expressed in individual neurons and both proteins co-localize in transfected cells, and immunoprecipitation indicates that the two polypeptides associate with each other probably as heterodimers. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Two proteins that each do almost nothing on their own make a working receptor only when put together. organism: Rat and human genes tissue_or_cell_type: Transfected cells and neurons experimental_model: Heterologous expression and immunoprecipitation of two GABA-B polypeptides with potassium channel readout limitations: Heterologous expression. The functional claim rests on channel activation in transfected cells rather than in native tissue. exposure: GABA-B R1 and R2 expressed alone and together, with GIRK-type potassium channel activity as the readout evidence_span: {"source_cache": "artifacts/gaba-research/9872315.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "c6687fd9eb8b7ebcc0496a2385b0201b02662a5fe8da87a0089650a150f00613", "start_char": 0, "end_char": 1473, "text_sha256": "c6687fd9eb8b7ebcc0496a2385b0201b02662a5fe8da87a0089650a150f00613"} [gb-p9872315] GABA(B) receptors function as a heteromeric assembly of the subunits GABA(B)R1 and GABA(B)R2. (1998). https://pubmed.ncbi.nlm.nih.gov/9872315/ DOI: 10.1038/25348

    Complete structured claim and evidence

16. A new GABA-B receptor subtype GABA-B R2 does not bind available GABA-B antagonists with measurable potency, GABA-B R1a, R1b and R2 alone do not activate Kir3-type potassium channels efficiently but co-expression yields a robust coupling to activation of Kir3 channels, there is evidence for assembly of heteromeric GABA-B receptors in vivo with the proteins immunoprecipitating and localizing together at dendritic spines, and the heteromeric receptor complexes exhibit a significant increase in agonist- and partial-agonist-binding potencies as compared with individual receptors and probably represent the predominant native GABA-B receptor.

    GABA-B receptor subunit 2 / GABBR2 → GABA-B receptor subunit 1 / GABBR1 source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/9872317.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "6a3eefc95d36d31151d094326c5d7f6dedd19b335dee29442de15b4b37ad9cfb", "start_char": 0, "end_char": 1620, "text_sha256": "6a3eefc95d36d31151d094326c5d7f6dedd19b335dee29442de15b4b37ad9cfb"}

    experimental_model

    Cloning of a second GABA-B subtype with binding potency and Kir3 channel coupling

    exposure

    GABA-B R1a, R1b and R2 expressed alone and in combination

    limitations

    A companion study reaching the same conclusion by a different route, including colocalisation at dendritic spines in vivo.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Rat

    plain_language

    Put the two subunits together and the receptor not only works but binds its agonist far better than either part did.

    primary_references

    [gb-p9872317] GABA(B)-receptor subtypes assemble into functional heteromeric complexes. (1998). https://pubmed.ncbi.nlm.nih.gov/9872317/ DOI: 10.1038/25360

    tissue_or_cell_type

    Transfected cells and dendritic spines

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 287–298

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Cloning of a second GABA-B subtype with binding potency and Kir3 channel coupling · source_derived_draft · unverified_draft

    ### gb-the-pair-binds-better-than-either A new GABA-B receptor subtype GABA-B R2 does not bind available GABA-B antagonists with measurable potency, GABA-B R1a, R1b and R2 alone do not activate Kir3-type potassium channels efficiently but co-expression yields a robust coupling to activation of Kir3 channels, there is evidence for assembly of heteromeric GABA-B receptors in vivo with the proteins immunoprecipitating and localizing together at dendritic spines, and the heteromeric receptor complexes exhibit a significant increase in agonist- and partial-agonist-binding potencies as compared with individual receptors and probably represent the predominant native GABA-B receptor. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Put the two subunits together and the receptor not only works but binds its agonist far better than either part did. organism: Rat tissue_or_cell_type: Transfected cells and dendritic spines experimental_model: Cloning of a second GABA-B subtype with binding potency and Kir3 channel coupling limitations: A companion study reaching the same conclusion by a different route, including colocalisation at dendritic spines in vivo. exposure: GABA-B R1a, R1b and R2 expressed alone and in combination evidence_span: {"source_cache": "artifacts/gaba-research/9872317.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "6a3eefc95d36d31151d094326c5d7f6dedd19b335dee29442de15b4b37ad9cfb", "start_char": 0, "end_char": 1620, "text_sha256": "6a3eefc95d36d31151d094326c5d7f6dedd19b335dee29442de15b4b37ad9cfb"} [gb-p9872317] GABA(B)-receptor subtypes assemble into functional heteromeric complexes. (1998). https://pubmed.ncbi.nlm.nih.gov/9872317/ DOI: 10.1038/25360

    Complete structured claim and evidence

17. Gabapentin is a novel anticonvulsant drug with a mechanism of action apparently dissimilar to that of other antiepileptic agents, the detergent-solubilized binding protein from pig cerebral cortex membranes was purified 1022-fold, the purified protein had an apparent subunit molecular weight of 130,000 and was heavily glycosylated, its partial N-terminal amino acid sequence EPFPSAVTIK was identical to that reported for the alpha2delta subunit of the L-type calcium channel, binding to cells transfected with alpha2delta complementary DNA was elevated more than 10-fold over controls, and tritiated gabapentin is the first pharmacological agent described that interacts with an alpha2delta subunit of a voltage-dependent calcium channel.

    Gabapentin → The alpha-2-delta subunit of a voltage-dependent calcium channel source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/8621444.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1723620d459b4f48ad397d59284df3f0619894ba82c6d066a42a47a0edb22216", "start_char": 0, "end_char": 1531, "text_sha256": "1723620d459b4f48ad397d59284df3f0619894ba82c6d066a42a47a0edb22216"}

    experimental_model

    Purification of a radioligand binding protein from pig cerebral cortex with N-terminal sequencing and expression in transfected cells

    exposure

    Tritiated gabapentin binding, followed through a six-step purification to protein identity

    limitations

    A binding and purification study. It identifies what the drug binds; it does not test the GABA receptors, so the absence of GABA-receptor binding is not measured here.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Pig and rat

    plain_language

    The anticonvulsant designed as a GABA analogue turned out to bind a calcium channel subunit instead.

    primary_references

    [gb-p8621444] The novel anticonvulsant drug, gabapentin (Neurontin), binds to the alpha2delta subunit of a calcium channel. (1996). https://pubmed.ncbi.nlm.nih.gov/8621444/ DOI: 10.1074/jbc.271.10.5768

    tissue_or_cell_type

    Cerebral cortex, heart and skeletal muscle

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 300–311

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Purification of a radioligand binding protein from pig cerebral cortex with N-terminal sequencing and expression in transfected cells · source_derived_draft · unverified_draft

    ### gb-the-drug-named-for-gaba-binds-a-calcium-channel Gabapentin is a novel anticonvulsant drug with a mechanism of action apparently dissimilar to that of other antiepileptic agents, the detergent-solubilized binding protein from pig cerebral cortex membranes was purified 1022-fold, the purified protein had an apparent subunit molecular weight of 130,000 and was heavily glycosylated, its partial N-terminal amino acid sequence EPFPSAVTIK was identical to that reported for the alpha2delta subunit of the L-type calcium channel, binding to cells transfected with alpha2delta complementary DNA was elevated more than 10-fold over controls, and tritiated gabapentin is the first pharmacological agent described that interacts with an alpha2delta subunit of a voltage-dependent calcium channel. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The anticonvulsant designed as a GABA analogue turned out to bind a calcium channel subunit instead. organism: Pig and rat tissue_or_cell_type: Cerebral cortex, heart and skeletal muscle experimental_model: Purification of a radioligand binding protein from pig cerebral cortex with N-terminal sequencing and expression in transfected cells limitations: A binding and purification study. It identifies what the drug binds; it does not test the GABA receptors, so the absence of GABA-receptor binding is not measured here. exposure: Tritiated gabapentin binding, followed through a six-step purification to protein identity evidence_span: {"source_cache": "artifacts/gaba-research/8621444.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1723620d459b4f48ad397d59284df3f0619894ba82c6d066a42a47a0edb22216", "start_char": 0, "end_char": 1531, "text_sha256": "1723620d459b4f48ad397d59284df3f0619894ba82c6d066a42a47a0edb22216"} [gb-p8621444] The novel anticonvulsant drug, gabapentin (Neurontin), binds to the alpha2delta subunit of a calcium channel. (1996). https://pubmed.ncbi.nlm.nih.gov/8621444/ DOI: 10.1074/jbc.271.10.5768

    Complete structured claim and evidence

18. In two multicentre double-blind randomised placebo-controlled phase 3 trials of brexanolone injection in women with post-partum depression, the least-squares mean reduction in Hamilton Rating Scale for Depression total score at 60 hours was significantly greater with brexanolone than with placebo, the treatment was generally well tolerated and the most common adverse events included headache, dizziness and somnolence, with sedation-related events leading to dose interruption or reduction in a small number of patients.

    Brexanolone, an intravenous allopregnanolone preparation → Hamilton Rating Scale for Depression total score source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/30177236.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e1fe6320cb8a13ea913662a0f648ef919eecbeeb47c742242c58ed4a342b2ceb", "start_char": 0, "end_char": 4369, "text_sha256": "e1fe6320cb8a13ea913662a0f648ef919eecbeeb47c742242c58ed4a342b2ceb"}

    experimental_model

    Two multicentre double-blind randomised placebo-controlled trials of a 60-hour intravenous infusion

    exposure

    Brexanolone, an intravenous formulation of the endogenous neurosteroid allopregnanolone, in severe and moderate postpartum depression

    limitations

    Two randomised trials with a depression rating scale as the endpoint over 60 hours of infusion, in a hospital setting.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Human

    plain_language

    An infusion of the body own calming steroid lifted depression scores within sixty hours.

    primary_references

    [gb-p30177236] Brexanolone injection in post-partum depression: two multicentre, double-blind, randomised, placebo-controlled, phase 3 trials. (2018). https://pubmed.ncbi.nlm.nih.gov/30177236/ DOI: 10.1016/s0140-6736(18)31551-4

    tissue_or_cell_type

    Central nervous system

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 313–324

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Two multicentre double-blind randomised placebo-controlled trials of a 60-hour intravenous infusion · source_derived_draft · unverified_draft

    ### gb-a-neurosteroid-works-in-postpartum-depression In two multicentre double-blind randomised placebo-controlled phase 3 trials of brexanolone injection in women with post-partum depression, the least-squares mean reduction in Hamilton Rating Scale for Depression total score at 60 hours was significantly greater with brexanolone than with placebo, the treatment was generally well tolerated and the most common adverse events included headache, dizziness and somnolence, with sedation-related events leading to dose interruption or reduction in a small number of patients. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: An infusion of the body own calming steroid lifted depression scores within sixty hours. organism: Human tissue_or_cell_type: Central nervous system experimental_model: Two multicentre double-blind randomised placebo-controlled trials of a 60-hour intravenous infusion limitations: Two randomised trials with a depression rating scale as the endpoint over 60 hours of infusion, in a hospital setting. exposure: Brexanolone, an intravenous formulation of the endogenous neurosteroid allopregnanolone, in severe and moderate postpartum depression evidence_span: {"source_cache": "artifacts/gaba-research/30177236.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e1fe6320cb8a13ea913662a0f648ef919eecbeeb47c742242c58ed4a342b2ceb", "start_char": 0, "end_char": 4369, "text_sha256": "e1fe6320cb8a13ea913662a0f648ef919eecbeeb47c742242c58ed4a342b2ceb"} [gb-p30177236] Brexanolone injection in post-partum depression: two multicentre, double-blind, randomised, placebo-controlled, phase 3 trials. (2018). https://pubmed.ncbi.nlm.nih.gov/30177236/ DOI: 10.1016/s0140-6736(18)31551-4

    Complete structured claim and evidence

19. GABA transport was studied by cellular uptake of tritiated GABA which was sodium-, chloride- and concentration-dependent with a Michaelis-Menten constant of 679 plus or minus 80 micromol per litre and a maximal uptake rate of 4,790 pmol per milligram protein per 5 minutes, uptake was significantly inhibited by betaine, beta-alanine, nipecotic acid, taurine and quinidine whereas probenecid, L-proline, creatine and glycine had no effect, and confocal immunofluorescent microscopy demonstrated colocalization of GAT2/BGT-1 with P-glycoprotein, a barrier-specific marker, on brain capillaries.

    The GABA transporter GAT2 / BGT-1 → Gamma-aminobutyric acid source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/11598501.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "97e62b677991c2535e9cd91c1283edc6415a64f66def965c17e478f7b676f708", "start_char": 0, "end_char": 1589, "text_sha256": "97e62b677991c2535e9cd91c1283edc6415a64f66def965c17e478f7b676f708"}

    experimental_model

    Reverse transcription PCR, Western blot and confocal immunostaining with uptake kinetics in an immortalised brain capillary endothelial line

    exposure

    Tritiated GABA uptake by a conditionally immortalised mouse brain capillary endothelial cell line used as an in vitro barrier model

    limitations

    An in vitro barrier model. It identifies the transporter and its kinetics; it does not establish the direction of net flux across an intact barrier.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    The barrier has a dedicated carrier for this molecule, and its affinity is low enough that it only moves appreciable amounts at high concentrations.

    primary_references

    [gb-p11598501] GAT2/BGT-1 as a system responsible for the transport of gamma-aminobutyric acid at the mouse blood-brain barrier. (2001). https://pubmed.ncbi.nlm.nih.gov/11598501/ DOI: 10.1097/00004647-200110000-00012

    tissue_or_cell_type

    Brain capillary endothelium

    transport_effect

    raises Measured as cellular uptake of tritiated GABA, sodium- and chloride-dependent.

    transport_pool

    the expressing cell Measured as cellular uptake of tritiated GABA, sodium- and chloride-dependent.

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 326–337

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Reverse transcription PCR, Western blot and confocal immunostaining with uptake kinetics in an immortalised brain capillary endothelial line · source_derived_draft · unverified_draft

    ### gb-a-transporter-handles-gaba-at-the-barrier GABA transport was studied by cellular uptake of tritiated GABA which was sodium-, chloride- and concentration-dependent with a Michaelis-Menten constant of 679 plus or minus 80 micromol per litre and a maximal uptake rate of 4,790 pmol per milligram protein per 5 minutes, uptake was significantly inhibited by betaine, beta-alanine, nipecotic acid, taurine and quinidine whereas probenecid, L-proline, creatine and glycine had no effect, and confocal immunofluorescent microscopy demonstrated colocalization of GAT2/BGT-1 with P-glycoprotein, a barrier-specific marker, on brain capillaries. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The barrier has a dedicated carrier for this molecule, and its affinity is low enough that it only moves appreciable amounts at high concentrations. organism: Mouse tissue_or_cell_type: Brain capillary endothelium experimental_model: Reverse transcription PCR, Western blot and confocal immunostaining with uptake kinetics in an immortalised brain capillary endothelial line limitations: An in vitro barrier model. It identifies the transporter and its kinetics; it does not establish the direction of net flux across an intact barrier. exposure: Tritiated GABA uptake by a conditionally immortalised mouse brain capillary endothelial cell line used as an in vitro barrier model evidence_span: {"source_cache": "artifacts/gaba-research/11598501.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "97e62b677991c2535e9cd91c1283edc6415a64f66def965c17e478f7b676f708", "start_char": 0, "end_char": 1589, "text_sha256": "97e62b677991c2535e9cd91c1283edc6415a64f66def965c17e478f7b676f708"} [gb-p11598501] GAT2/BGT-1 as a system responsible for the transport of gamma-aminobutyric acid at the mouse blood-brain barrier. (2001). https://pubmed.ncbi.nlm.nih.gov/11598501/ DOI: 10.1097/00004647-200110000-00012

    Complete structured claim and evidence

20. Study of brain to blood efflux transport of carbon-14 GABA after loading the brain by vascular perfusion revealed that the half-time of elimination was significantly shorter in spontaneously hypertensive rats at 5.35 plus or minus 0.66 minutes than in Wistar Kyoto rats at 14.83 plus or minus 1.94 minutes, the faster efflux might at least partially compensate for increased uptake and preserve the protective function of the barrier towards GABA, and systemic infusion of GABA within a wide range of administered doses from 0.004 to 5.00 milligrams per kilogram produced an increase in cerebrospinal fluid GABA concentration from around 0.5 micromolar to only 11 micromolar.

    Brain-to-blood efflux transport of GABA → Cerebrospinal fluid GABA concentration source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/16616765.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "550c910f870ffc48b56fbcfe95555a4fec6441bdbef7b1369ef79d1bcba6df5d", "start_char": 0, "end_char": 1941, "text_sha256": "550c910f870ffc48b56fbcfe95555a4fec6441bdbef7b1369ef79d1bcba6df5d"}

    experimental_model

    In situ brain perfusion with efflux measurement and cerebrospinal fluid sampling across a range of systemic doses

    exposure

    Carbon-14 GABA by bilateral in situ brain perfusion, and systemic GABA infusion from 0.004 to 5.00 milligrams per kilogram

    limitations

    Anaesthetised rats, and the comparison is between hypertensive and normotensive strains. The dose-ranging cerebrospinal fluid measurement is the part that bears on oral supplementation.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Rat

    plain_language

    The brain actively pumps this molecule back out, and flooding the bloodstream with it barely shifts the concentration inside.

    primary_references

    [gb-p16616765] Increased brain uptake and brain to blood efflux transport of 14C-GABA in spontaneously hypertensive rats. (2006). https://pubmed.ncbi.nlm.nih.gov/16616765/ DOI: 10.1016/j.lfs.2006.02.039

    tissue_or_cell_type

    Brain, cerebrospinal fluid and cerebral capillaries

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 339–350

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · In situ brain perfusion with efflux measurement and cerebrospinal fluid sampling across a range of systemic doses · source_derived_draft · unverified_draft

    ### gb-the-brain-pushes-gaba-back-out Study of brain to blood efflux transport of carbon-14 GABA after loading the brain by vascular perfusion revealed that the half-time of elimination was significantly shorter in spontaneously hypertensive rats at 5.35 plus or minus 0.66 minutes than in Wistar Kyoto rats at 14.83 plus or minus 1.94 minutes, the faster efflux might at least partially compensate for increased uptake and preserve the protective function of the barrier towards GABA, and systemic infusion of GABA within a wide range of administered doses from 0.004 to 5.00 milligrams per kilogram produced an increase in cerebrospinal fluid GABA concentration from around 0.5 micromolar to only 11 micromolar. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The brain actively pumps this molecule back out, and flooding the bloodstream with it barely shifts the concentration inside. organism: Rat tissue_or_cell_type: Brain, cerebrospinal fluid and cerebral capillaries experimental_model: In situ brain perfusion with efflux measurement and cerebrospinal fluid sampling across a range of systemic doses limitations: Anaesthetised rats, and the comparison is between hypertensive and normotensive strains. The dose-ranging cerebrospinal fluid measurement is the part that bears on oral supplementation. exposure: Carbon-14 GABA by bilateral in situ brain perfusion, and systemic GABA infusion from 0.004 to 5.00 milligrams per kilogram evidence_span: {"source_cache": "artifacts/gaba-research/16616765.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "550c910f870ffc48b56fbcfe95555a4fec6441bdbef7b1369ef79d1bcba6df5d", "start_char": 0, "end_char": 1941, "text_sha256": "550c910f870ffc48b56fbcfe95555a4fec6441bdbef7b1369ef79d1bcba6df5d"} [gb-p16616765] Increased brain uptake and brain to blood efflux transport of 14C-GABA in spontaneously hypertensive rats. (2006). https://pubmed.ncbi.nlm.nih.gov/16616765/ DOI: 10.1016/j.lfs.2006.02.039

    Complete structured claim and evidence

21. The first study evaluated the effect of GABA intake by 13 subjects on their brain waves, with electroencephalograms obtained after three tests on each volunteer taking only water, GABA, or L-theanine, and after 60 minutes of administration GABA significantly increased alpha waves and decreased beta waves compared to water or L-theanine, while in a second study eight acrophobic subjects crossing a suspended bridge as a stressful stimulus showed a marked decrease of salivary immunoglobulin A in the placebo group while the GABA group showed significantly higher levels.

    Gamma-aminobutyric acid → Electroencephalographic alpha and beta wave power source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/16971751.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "f0958495814a3c685efcafef73349d34248a2648872afa7e4a92c93132d9b631", "start_char": 0, "end_char": 1322, "text_sha256": "f0958495814a3c685efcafef73349d34248a2648872afa7e4a92c93132d9b631"}

    experimental_model

    Two small studies: electroencephalography after a single intake, and salivary immunoglobulin during a stressor

    exposure

    Orally administered GABA against water and against L-theanine, and GABA against placebo in acrophobic subjects crossing a suspended bridge

    limitations

    Thirteen subjects in the first study and eight in the second, with no correction for multiple comparisons reported. The immunity claim rests on salivary immunoglobulin A in eight people.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Human

    plain_language

    A gram taken by mouth changed the pattern of brain waves within an hour in thirteen people.

    primary_references

    [gb-p16971751] Relaxation and immunity enhancement effects of gamma-aminobutyric acid (GABA) administration in humans. (2006). https://pubmed.ncbi.nlm.nih.gov/16971751/ DOI: 10.1002/biof.5520260305

    tissue_or_cell_type

    Brain electrical activity and saliva

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 352–363

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Two small studies: electroencephalography after a single intake, and salivary immunoglobulin during a stressor · source_derived_draft · unverified_draft

    ### gb-oral-gaba-shifts-the-eeg The first study evaluated the effect of GABA intake by 13 subjects on their brain waves, with electroencephalograms obtained after three tests on each volunteer taking only water, GABA, or L-theanine, and after 60 minutes of administration GABA significantly increased alpha waves and decreased beta waves compared to water or L-theanine, while in a second study eight acrophobic subjects crossing a suspended bridge as a stressful stimulus showed a marked decrease of salivary immunoglobulin A in the placebo group while the GABA group showed significantly higher levels. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: A gram taken by mouth changed the pattern of brain waves within an hour in thirteen people. organism: Human tissue_or_cell_type: Brain electrical activity and saliva experimental_model: Two small studies: electroencephalography after a single intake, and salivary immunoglobulin during a stressor limitations: Thirteen subjects in the first study and eight in the second, with no correction for multiple comparisons reported. The immunity claim rests on salivary immunoglobulin A in eight people. exposure: Orally administered GABA against water and against L-theanine, and GABA against placebo in acrophobic subjects crossing a suspended bridge evidence_span: {"source_cache": "artifacts/gaba-research/16971751.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "f0958495814a3c685efcafef73349d34248a2648872afa7e4a92c93132d9b631", "start_char": 0, "end_char": 1322, "text_sha256": "f0958495814a3c685efcafef73349d34248a2648872afa7e4a92c93132d9b631"} [gb-p16971751] Relaxation and immunity enhancement effects of gamma-aminobutyric acid (GABA) administration in humans. (2006). https://pubmed.ncbi.nlm.nih.gov/16971751/ DOI: 10.1002/biof.5520260305

    Complete structured claim and evidence

22. In 39 mildly hypertensive adults divided into a test group of 22 who consumed rice with 11.2 milligrams GABA per 100 grams and a placebo group of 17 who consumed rice with 2.7 milligrams per 100 grams for 8 weeks, although the hospital blood pressure and evening blood pressure measurements of the participants showed no significant change, consumption of the GABA rice improved the morning blood pressure compared with the placebo rice after the first week and during the sixth and eighth weeks.

    A GABA-enriched food or supplement preparation → Self-measured morning blood pressure source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/26870683.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "9567c5c241e58810e0ccbf83890474aeffb6ea63198864ba199bee68708482e4", "start_char": 0, "end_char": 1173, "text_sha256": "9567c5c241e58810e0ccbf83890474aeffb6ea63198864ba199bee68708482e4"}

    experimental_model

    Randomised double-blind placebo-controlled study with home self-measured blood pressure over eight weeks

    exposure

    White rice enriched to 11.2 milligrams GABA per 100 grams against rice with 2.7 milligrams per 100 grams, 150 grams daily

    limitations

    Thirty-nine mildly hypertensive adults. Hospital and evening blood pressure did not change, so the positive result is confined to one of the three measurement settings.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Human

    plain_language

    Enriched rice moved the morning readings and left the clinic and evening readings alone.

    primary_references

    [gb-p26870683] Effects of white rice containing enriched gamma-aminobutyric acid on blood pressure. (2016). https://pubmed.ncbi.nlm.nih.gov/26870683/ DOI: 10.1016/j.jtcme.2014.11.022

    tissue_or_cell_type

    Systemic circulation

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 365–376

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomised double-blind placebo-controlled study with home self-measured blood pressure over eight weeks · source_derived_draft · unverified_draft

    ### gb-only-morning-pressure-moved In 39 mildly hypertensive adults divided into a test group of 22 who consumed rice with 11.2 milligrams GABA per 100 grams and a placebo group of 17 who consumed rice with 2.7 milligrams per 100 grams for 8 weeks, although the hospital blood pressure and evening blood pressure measurements of the participants showed no significant change, consumption of the GABA rice improved the morning blood pressure compared with the placebo rice after the first week and during the sixth and eighth weeks. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Enriched rice moved the morning readings and left the clinic and evening readings alone. organism: Human tissue_or_cell_type: Systemic circulation experimental_model: Randomised double-blind placebo-controlled study with home self-measured blood pressure over eight weeks limitations: Thirty-nine mildly hypertensive adults. Hospital and evening blood pressure did not change, so the positive result is confined to one of the three measurement settings. exposure: White rice enriched to 11.2 milligrams GABA per 100 grams against rice with 2.7 milligrams per 100 grams, 150 grams daily evidence_span: {"source_cache": "artifacts/gaba-research/26870683.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "9567c5c241e58810e0ccbf83890474aeffb6ea63198864ba199bee68708482e4", "start_char": 0, "end_char": 1173, "text_sha256": "9567c5c241e58810e0ccbf83890474aeffb6ea63198864ba199bee68708482e4"} [gb-p26870683] Effects of white rice containing enriched gamma-aminobutyric acid on blood pressure. (2016). https://pubmed.ncbi.nlm.nih.gov/26870683/ DOI: 10.1016/j.jtcme.2014.11.022

    Complete structured claim and evidence

23. Eighty subjects with systolic blood pressure 130 to 159 millimetres of mercury or diastolic 85 to 99 took GABA-rich Chlorella supplying 20 milligrams as gamma-aminobutyric acid or placebo twice daily for 12 weeks with follow-up for an additional 4 weeks, systolic blood pressure in the subjects given GABA-rich Chlorella significantly decreased compared with placebo, diastolic blood pressure had the tendency to decrease, neither adverse events nor abnormal laboratory findings were reported, and reduction of systolic pressure in the subjects with borderline hypertension was higher than in those with high-normal blood pressure.

    A GABA-enriched food or supplement preparation → Systolic blood pressure source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/19811362.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "f372e3ce2c34cf5dcbac79af1c003b562d14665f547fab69748c5ee625c34886", "start_char": 0, "end_char": 1307, "text_sha256": "f372e3ce2c34cf5dcbac79af1c003b562d14665f547fab69748c5ee625c34886"}

    experimental_model

    Placebo-controlled double-blind study over twelve weeks with four weeks of follow-up

    exposure

    GABA-rich Chlorella supplying 20 milligrams of GABA twice daily against placebo

    limitations

    Eighty subjects with high-normal or borderline blood pressure. The intervention is a whole algal preparation, so the effect is not attributable to GABA alone.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Human

    plain_language

    Twelve weeks of a GABA-rich algal supplement lowered the upper blood pressure reading.

    primary_references

    [gb-p19811362] Anti-hypertensive effect of gamma-aminobutyric acid (GABA)-rich Chlorella on high-normal blood pressure and borderline hypertension in placebo-controlled double blind study. (2009). https://pubmed.ncbi.nlm.nih.gov/19811362/ DOI: 10.1080/10641960902977908

    tissue_or_cell_type

    Systemic circulation

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 378–389

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Placebo-controlled double-blind study over twelve weeks with four weeks of follow-up · source_derived_draft · unverified_draft

    ### gb-an-algal-preparation-lowered-pressure Eighty subjects with systolic blood pressure 130 to 159 millimetres of mercury or diastolic 85 to 99 took GABA-rich Chlorella supplying 20 milligrams as gamma-aminobutyric acid or placebo twice daily for 12 weeks with follow-up for an additional 4 weeks, systolic blood pressure in the subjects given GABA-rich Chlorella significantly decreased compared with placebo, diastolic blood pressure had the tendency to decrease, neither adverse events nor abnormal laboratory findings were reported, and reduction of systolic pressure in the subjects with borderline hypertension was higher than in those with high-normal blood pressure. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Twelve weeks of a GABA-rich algal supplement lowered the upper blood pressure reading. organism: Human tissue_or_cell_type: Systemic circulation experimental_model: Placebo-controlled double-blind study over twelve weeks with four weeks of follow-up limitations: Eighty subjects with high-normal or borderline blood pressure. The intervention is a whole algal preparation, so the effect is not attributable to GABA alone. exposure: GABA-rich Chlorella supplying 20 milligrams of GABA twice daily against placebo evidence_span: {"source_cache": "artifacts/gaba-research/19811362.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "f372e3ce2c34cf5dcbac79af1c003b562d14665f547fab69748c5ee625c34886", "start_char": 0, "end_char": 1307, "text_sha256": "f372e3ce2c34cf5dcbac79af1c003b562d14665f547fab69748c5ee625c34886"} [gb-p19811362] Anti-hypertensive effect of gamma-aminobutyric acid (GABA)-rich Chlorella on high-normal blood pressure and borderline hypertension in placebo-controlled double blind study. (2009). https://pubmed.ncbi.nlm.nih.gov/19811362/ DOI: 10.1080/10641960902977908

    Complete structured claim and evidence

24. In volunteers with mildly or moderately high blood pressure, both the fermented drinking water containing gamma-aminobutyric acid and the placebo drink of vinegar and dried bonito without GABA significantly decreased systolic blood pressure by 7.6 plus or minus 4.0 and 5.5 plus or minus 1.5 millimetres of mercury respectively and diastolic by 10.6 plus or minus 4.0 and 7.6 plus or minus 1.7 millimetres of mercury respectively compared to baseline at 12 weeks, there were no abnormal changes in haematological or blood chemistry variables, and these findings indicated that vinegar and dried bonito with or without GABA might have an effect on blood pressure.

    The fermented vinegar and dried bonito drink without added GABA → Systolic blood pressure source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/19590713.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "cf28abaa2c4005e26679a43d2ee25123d4ca6fb7184943a6b8c7e0529e560e4a", "start_char": 0, "end_char": 1206, "text_sha256": "cf28abaa2c4005e26679a43d2ee25123d4ca6fb7184943a6b8c7e0529e560e4a"}

    experimental_model

    Double-blind placebo-controlled randomised study with the same fermented drink prepared with and without GABA

    exposure

    Fermented drinking water from sodium glutamate, vinegar and dried bonito, against the identical drink without GABA

    limitations

    The control is the same food matrix minus the GABA, which is the comparison the other blood-pressure studies lack.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Human

    plain_language

    The drink without any GABA in it lowered blood pressure too, which is what the other trials had no way of detecting.

    primary_references

    [gb-p19590713] The Effects of gamma-Aminobutyric Acid, Vinegar, and Dried Bonito on Blood Pressure in Normotensive and Mildly or Moderately Hypertensive Volunteers. (2009). https://pubmed.ncbi.nlm.nih.gov/19590713/ DOI: 10.3164/jcbn.09-04

    tissue_or_cell_type

    Systemic circulation

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 391–402

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Double-blind placebo-controlled randomised study with the same fermented drink prepared with and without GABA · source_derived_draft · unverified_draft

    ### gb-the-control-worked-too In volunteers with mildly or moderately high blood pressure, both the fermented drinking water containing gamma-aminobutyric acid and the placebo drink of vinegar and dried bonito without GABA significantly decreased systolic blood pressure by 7.6 plus or minus 4.0 and 5.5 plus or minus 1.5 millimetres of mercury respectively and diastolic by 10.6 plus or minus 4.0 and 7.6 plus or minus 1.7 millimetres of mercury respectively compared to baseline at 12 weeks, there were no abnormal changes in haematological or blood chemistry variables, and these findings indicated that vinegar and dried bonito with or without GABA might have an effect on blood pressure. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The drink without any GABA in it lowered blood pressure too, which is what the other trials had no way of detecting. organism: Human tissue_or_cell_type: Systemic circulation experimental_model: Double-blind placebo-controlled randomised study with the same fermented drink prepared with and without GABA limitations: The control is the same food matrix minus the GABA, which is the comparison the other blood-pressure studies lack. exposure: Fermented drinking water from sodium glutamate, vinegar and dried bonito, against the identical drink without GABA evidence_span: {"source_cache": "artifacts/gaba-research/19590713.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "cf28abaa2c4005e26679a43d2ee25123d4ca6fb7184943a6b8c7e0529e560e4a", "start_char": 0, "end_char": 1206, "text_sha256": "cf28abaa2c4005e26679a43d2ee25123d4ca6fb7184943a6b8c7e0529e560e4a"} [gb-p19590713] The Effects of gamma-Aminobutyric Acid, Vinegar, and Dried Bonito on Blood Pressure in Normotensive and Mildly or Moderately Hypertensive Volunteers. (2009). https://pubmed.ncbi.nlm.nih.gov/19590713/ DOI: 10.3164/jcbn.09-04

    Complete structured claim and evidence

25. The inhibitory neurotransmitter GABA is present in the endocrine part of the pancreas at concentrations comparable to those encountered in the central nervous system and co-localizes with insulin in pancreatic beta cells, and we describe a mechanism whereby GABA co-secreted with insulin from beta cells may mediate part of the inhibitory action of glucose on glucagon secretion by activating GABA-A receptor chloride channels in alpha 2 cells, providing a model for feedback regulation of glucagon release which may be of significance for understanding the hypersecretion of glucagon frequently associated with diabetes.

    Gamma-aminobutyric acid → Glucagon secretion source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/2550826.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "9062539804213a1ccf427b75c8f6d262b151e22464cd6b7c84640f222f7dea94", "start_char": 0, "end_char": 1225, "text_sha256": "9062539804213a1ccf427b75c8f6d262b151e22464cd6b7c84640f222f7dea94"}

    experimental_model

    Electrophysiology of pancreatic alpha 2 cells with glucose and GABA

    exposure

    GABA co-secreted with insulin from beta cells, acting on GABA-A receptor chloride channels in alpha 2 cells

    limitations

    An early electrophysiological model. It proposes that GABA mediates part of the effect of glucose rather than demonstrating the whole of it.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Guinea pig and rat

    plain_language

    The cells that release insulin release GABA with it, and that is part of how a meal switches off the opposing hormone.

    primary_references

    [gb-p2550826] Glucose-inhibition of glucagon secretion involves activation of GABAA-receptor chloride channels. (1989). https://pubmed.ncbi.nlm.nih.gov/2550826/ DOI: 10.1038/341233a0

    tissue_or_cell_type

    Pancreatic islet

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 404–415

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Electrophysiology of pancreatic alpha 2 cells with glucose and GABA · source_derived_draft · unverified_draft

    ### gb-the-islet-signals-with-gaba The inhibitory neurotransmitter GABA is present in the endocrine part of the pancreas at concentrations comparable to those encountered in the central nervous system and co-localizes with insulin in pancreatic beta cells, and we describe a mechanism whereby GABA co-secreted with insulin from beta cells may mediate part of the inhibitory action of glucose on glucagon secretion by activating GABA-A receptor chloride channels in alpha 2 cells, providing a model for feedback regulation of glucagon release which may be of significance for understanding the hypersecretion of glucagon frequently associated with diabetes. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The cells that release insulin release GABA with it, and that is part of how a meal switches off the opposing hormone. organism: Guinea pig and rat tissue_or_cell_type: Pancreatic islet experimental_model: Electrophysiology of pancreatic alpha 2 cells with glucose and GABA limitations: An early electrophysiological model. It proposes that GABA mediates part of the effect of glucose rather than demonstrating the whole of it. exposure: GABA co-secreted with insulin from beta cells, acting on GABA-A receptor chloride channels in alpha 2 cells evidence_span: {"source_cache": "artifacts/gaba-research/2550826.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "9062539804213a1ccf427b75c8f6d262b151e22464cd6b7c84640f222f7dea94", "start_char": 0, "end_char": 1225, "text_sha256": "9062539804213a1ccf427b75c8f6d262b151e22464cd6b7c84640f222f7dea94"} [gb-p2550826] Glucose-inhibition of glucagon secretion involves activation of GABAA-receptor chloride channels. (1989). https://pubmed.ncbi.nlm.nih.gov/2550826/ DOI: 10.1038/341233a0

    Complete structured claim and evidence

26. Rat beta-cells release GABA by calcium-dependent exocytosis of synaptic-like microvesicles and the GABA thus released can diffuse over sufficient distances within the islet interstitium to activate GABA-A receptors in neighboring cells, confocal immunocytochemistry revealed the presence of GABA-A receptors in glucagon-secreting alpha-cells but not in beta- and delta-cells with transcripts of alpha1, alpha4 and beta1-3 subunits detected in purified alpha-cells but not in beta-cells, the antagonist SR95531 increased glucagon secretion at 1 millimolar glucose twofold and completely abolished the inhibitory action of 20 millimolar glucose on glucagon release, and basal and glucose-stimulated secretion of insulin and somatostatin were unaffected.

    SR95531, a GABA-A receptor antagonist → Glucagon secretion source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/15047619.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1f64e75f4c5822ecc05331804e4d127c8b1702249327c4ed85fa07d96898d5b0", "start_char": 0, "end_char": 1478, "text_sha256": "1f64e75f4c5822ecc05331804e4d127c8b1702249327c4ed85fa07d96898d5b0"}

    experimental_model

    Confocal immunocytochemistry, transcript analysis, whole-cell voltage clamp and hormone secretion with a receptor antagonist

    exposure

    Endogenous GABA released from beta cells, with the GABA-A antagonist SR95531 and the calcium channel blocker isradipine

    limitations

    The antagonist experiment is what makes this causal for the endogenous signal. Receptor detection was by immunocytochemistry and transcripts in purified cells.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Rat

    plain_language

    Block the receptor and glucose stops switching off glucagon entirely, and the receptor is on the glucagon cell and not on the insulin cell.

    primary_references

    [gb-p15047619] Glucose inhibition of glucagon secretion from rat alpha-cells is mediated by GABA released from neighboring beta-cells. (2004). https://pubmed.ncbi.nlm.nih.gov/15047619/ DOI: 10.2337/diabetes.53.4.1038

    tissue_or_cell_type

    Purified islet cells and intact islets

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 417–428

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Confocal immunocytochemistry, transcript analysis, whole-cell voltage clamp and hormone secretion with a receptor antagonist · source_derived_draft · unverified_draft

    ### gb-the-receptor-is-on-the-alpha-cell-only Rat beta-cells release GABA by calcium-dependent exocytosis of synaptic-like microvesicles and the GABA thus released can diffuse over sufficient distances within the islet interstitium to activate GABA-A receptors in neighboring cells, confocal immunocytochemistry revealed the presence of GABA-A receptors in glucagon-secreting alpha-cells but not in beta- and delta-cells with transcripts of alpha1, alpha4 and beta1-3 subunits detected in purified alpha-cells but not in beta-cells, the antagonist SR95531 increased glucagon secretion at 1 millimolar glucose twofold and completely abolished the inhibitory action of 20 millimolar glucose on glucagon release, and basal and glucose-stimulated secretion of insulin and somatostatin were unaffected. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Block the receptor and glucose stops switching off glucagon entirely, and the receptor is on the glucagon cell and not on the insulin cell. organism: Rat tissue_or_cell_type: Purified islet cells and intact islets experimental_model: Confocal immunocytochemistry, transcript analysis, whole-cell voltage clamp and hormone secretion with a receptor antagonist limitations: The antagonist experiment is what makes this causal for the endogenous signal. Receptor detection was by immunocytochemistry and transcripts in purified cells. exposure: Endogenous GABA released from beta cells, with the GABA-A antagonist SR95531 and the calcium channel blocker isradipine evidence_span: {"source_cache": "artifacts/gaba-research/15047619.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "1f64e75f4c5822ecc05331804e4d127c8b1702249327c4ed85fa07d96898d5b0", "start_char": 0, "end_char": 1478, "text_sha256": "1f64e75f4c5822ecc05331804e4d127c8b1702249327c4ed85fa07d96898d5b0"} [gb-p15047619] Glucose inhibition of glucagon secretion from rat alpha-cells is mediated by GABA released from neighboring beta-cells. (2004). https://pubmed.ncbi.nlm.nih.gov/15047619/ DOI: 10.2337/diabetes.53.4.1038

    Complete structured claim and evidence

27. Unlike in adult brain or islet alpha-cells in which GABA exerts hyperpolarizing effects, in islet beta-cells GABA produces membrane depolarization and calcium influx leading to the activation of PI3-kinase and Akt-dependent growth and survival pathways, this provides a potential mechanism underlying findings that GABA therapy preserves beta-cell mass and prevents the development of type 1 diabetes, remarkably in severely diabetic mice GABA restores beta-cell mass and reverses the disease, and GABA suppresses insulitis and systemic inflammatory cytokine production.

    Gamma-aminobutyric acid → Pancreatic islet beta cell source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/21709230.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "926bc916592c55cf6089bcb240ec5545e0ff3850e6d927bb82efacfc61841175", "start_char": 0, "end_char": 1117, "text_sha256": "926bc916592c55cf6089bcb240ec5545e0ff3850e6d927bb82efacfc61841175"}

    experimental_model

    Islet cell electrophysiology and signalling with GABA therapy in diabetes-prone and severely diabetic mice

    exposure

    GABA given therapeutically, with membrane potential, calcium influx and survival pathway readouts in beta cells

    limitations

    A mouse therapy study. Its electrophysiological claim about beta cells is stated as a contrast with alpha cells and brain rather than shown alongside a measured chloride gradient.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    In the insulin-producing cell the same molecule does the opposite of what it does in the brain, and the cells survive better for it.

    primary_references

    [gb-p21709230] GABA exerts protective and regenerative effects on islet beta cells and reverses diabetes. (2011). https://pubmed.ncbi.nlm.nih.gov/21709230/ DOI: 10.1073/pnas.1102715108

    tissue_or_cell_type

    Pancreatic islet and immune system

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 430–441

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Islet cell electrophysiology and signalling with GABA therapy in diabetes-prone and severely diabetic mice · source_derived_draft · unverified_draft

    ### gb-gaba-depolarises-the-beta-cell Unlike in adult brain or islet alpha-cells in which GABA exerts hyperpolarizing effects, in islet beta-cells GABA produces membrane depolarization and calcium influx leading to the activation of PI3-kinase and Akt-dependent growth and survival pathways, this provides a potential mechanism underlying findings that GABA therapy preserves beta-cell mass and prevents the development of type 1 diabetes, remarkably in severely diabetic mice GABA restores beta-cell mass and reverses the disease, and GABA suppresses insulitis and systemic inflammatory cytokine production. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: In the insulin-producing cell the same molecule does the opposite of what it does in the brain, and the cells survive better for it. organism: Mouse tissue_or_cell_type: Pancreatic islet and immune system experimental_model: Islet cell electrophysiology and signalling with GABA therapy in diabetes-prone and severely diabetic mice limitations: A mouse therapy study. Its electrophysiological claim about beta cells is stated as a contrast with alpha cells and brain rather than shown alongside a measured chloride gradient. exposure: GABA given therapeutically, with membrane potential, calcium influx and survival pathway readouts in beta cells evidence_span: {"source_cache": "artifacts/gaba-research/21709230.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "926bc916592c55cf6089bcb240ec5545e0ff3850e6d927bb82efacfc61841175", "start_char": 0, "end_char": 1117, "text_sha256": "926bc916592c55cf6089bcb240ec5545e0ff3850e6d927bb82efacfc61841175"} [gb-p21709230] GABA exerts protective and regenerative effects on islet beta cells and reverses diabetes. (2011). https://pubmed.ncbi.nlm.nih.gov/21709230/ DOI: 10.1073/pnas.1102715108

    Complete structured claim and evidence

28. GABA was identified as an inducer of alpha-to-beta-like cell conversion in vivo, this conversion induces alpha cell replacement mechanisms through the mobilization of duct-lining precursor cells that adopt an alpha cell identity prior to being converted into beta-like cells solely upon sustained GABA exposure, these neo-generated beta-like cells are functional and can repeatedly reverse chemically induced diabetes in vivo, and similarly the treatment of transplanted human islets with GABA results in a loss of alpha cells and a concomitant increase in beta-like cell counts suggestive of alpha-to-beta-like cell conversion processes also in humans.

    Gamma-aminobutyric acid → Conversion of alpha cells into beta-like cells source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/27916274.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4be6f165f91fed2e5ce13c111ae778fef006821e139b2702a3833f5924a4fffd", "start_char": 0, "end_char": 1087, "text_sha256": "4be6f165f91fed2e5ce13c111ae778fef006821e139b2702a3833f5924a4fffd"}

    experimental_model

    Lineage tracing and functional testing in mice with sustained GABA exposure, and treatment of transplanted human islets

    exposure

    Sustained long-term GABA administration in vivo, and GABA treatment of transplanted human islets

    limitations

    The human component is transplanted islets rather than people, and the cell counts are suggestive of conversion rather than a lineage trace in human tissue.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    Given long enough, the molecule appeared to turn one islet cell type into the other, repeatedly reversing diabetes in mice.

    primary_references

    [gb-p27916274] Long-Term GABA Administration Induces Alpha Cell-Mediated Beta-like Cell Neogenesis. (2017). https://pubmed.ncbi.nlm.nih.gov/27916274/ DOI: 10.1016/j.cell.2016.11.002

    tissue_or_cell_type

    Pancreatic islet and duct

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 443–454

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Lineage tracing and functional testing in mice with sustained GABA exposure, and treatment of transplanted human islets · source_derived_draft · unverified_draft

    ### gb-sustained-gaba-makes-new-beta-like-cells GABA was identified as an inducer of alpha-to-beta-like cell conversion in vivo, this conversion induces alpha cell replacement mechanisms through the mobilization of duct-lining precursor cells that adopt an alpha cell identity prior to being converted into beta-like cells solely upon sustained GABA exposure, these neo-generated beta-like cells are functional and can repeatedly reverse chemically induced diabetes in vivo, and similarly the treatment of transplanted human islets with GABA results in a loss of alpha cells and a concomitant increase in beta-like cell counts suggestive of alpha-to-beta-like cell conversion processes also in humans. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Given long enough, the molecule appeared to turn one islet cell type into the other, repeatedly reversing diabetes in mice. organism: Mouse tissue_or_cell_type: Pancreatic islet and duct experimental_model: Lineage tracing and functional testing in mice with sustained GABA exposure, and treatment of transplanted human islets limitations: The human component is transplanted islets rather than people, and the cell counts are suggestive of conversion rather than a lineage trace in human tissue. exposure: Sustained long-term GABA administration in vivo, and GABA treatment of transplanted human islets evidence_span: {"source_cache": "artifacts/gaba-research/27916274.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4be6f165f91fed2e5ce13c111ae778fef006821e139b2702a3833f5924a4fffd", "start_char": 0, "end_char": 1087, "text_sha256": "4be6f165f91fed2e5ce13c111ae778fef006821e139b2702a3833f5924a4fffd"} [gb-p27916274] Long-Term GABA Administration Induces Alpha Cell-Mediated Beta-like Cell Neogenesis. (2017). https://pubmed.ncbi.nlm.nih.gov/27916274/ DOI: 10.1016/j.cell.2016.11.002

    Complete structured claim and evidence

29. We studied 334 patients aged 10 to 20 years with type 1 diabetes, fasting C-peptide levels of more than 0.3 nanograms per millilitre and detectable serum GAD65 autoantibodies, randomly assigned within 3 months after diagnosis to four doses of GAD-alum, two doses followed by two doses of placebo, or four doses of placebo, the stimulated C-peptide level declined to a similar degree in all study groups and the primary outcome at 15 months did not differ significantly between the combined active-drug groups and the placebo group with P = 0.10, and the use of GAD-alum did not affect the insulin dose, glycated haemoglobin level or hypoglycaemia rate.

    Alum-formulated GAD65 antigen therapy → Stimulated serum C-peptide after a mixed-meal tolerance test source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/22296077.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "fc3bf9a083b3179c8573e993fb61f09412eca7890c3ccfb3ba5b8c0fb26acce8", "start_char": 0, "end_char": 1683, "text_sha256": "fc3bf9a083b3179c8573e993fb61f09412eca7890c3ccfb3ba5b8c0fb26acce8"}

    experimental_model

    Randomised placebo-controlled trial of an alum-formulated autoantigen in 334 patients within three months of diagnosis

    exposure

    Four doses of GAD-alum, two doses followed by placebo, or four doses of placebo, in patients aged 10 to 20 with detectable GAD65 autoantibodies

    limitations

    A properly powered randomised trial with stimulated C-peptide as the primary outcome. It tests the autoantigen as a therapy, not GABA.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Human

    plain_language

    Vaccinating against the enzyme the immune system attacks did not slow the loss of insulin production.

    primary_references

    [gb-p22296077] GAD65 antigen therapy in recently diagnosed type 1 diabetes mellitus. (2012). https://pubmed.ncbi.nlm.nih.gov/22296077/ DOI: 10.1056/nejmoa1107096

    tissue_or_cell_type

    Pancreatic beta cell function

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 456–467

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomised placebo-controlled trial of an alum-formulated autoantigen in 334 patients within three months of diagnosis · source_derived_draft · unverified_draft

    ### gb-targeting-the-autoantigen-did-not-work We studied 334 patients aged 10 to 20 years with type 1 diabetes, fasting C-peptide levels of more than 0.3 nanograms per millilitre and detectable serum GAD65 autoantibodies, randomly assigned within 3 months after diagnosis to four doses of GAD-alum, two doses followed by two doses of placebo, or four doses of placebo, the stimulated C-peptide level declined to a similar degree in all study groups and the primary outcome at 15 months did not differ significantly between the combined active-drug groups and the placebo group with P = 0.10, and the use of GAD-alum did not affect the insulin dose, glycated haemoglobin level or hypoglycaemia rate. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Vaccinating against the enzyme the immune system attacks did not slow the loss of insulin production. organism: Human tissue_or_cell_type: Pancreatic beta cell function experimental_model: Randomised placebo-controlled trial of an alum-formulated autoantigen in 334 patients within three months of diagnosis limitations: A properly powered randomised trial with stimulated C-peptide as the primary outcome. It tests the autoantigen as a therapy, not GABA. exposure: Four doses of GAD-alum, two doses followed by placebo, or four doses of placebo, in patients aged 10 to 20 with detectable GAD65 autoantibodies evidence_span: {"source_cache": "artifacts/gaba-research/22296077.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "fc3bf9a083b3179c8573e993fb61f09412eca7890c3ccfb3ba5b8c0fb26acce8", "start_char": 0, "end_char": 1683, "text_sha256": "fc3bf9a083b3179c8573e993fb61f09412eca7890c3ccfb3ba5b8c0fb26acce8"} [gb-p22296077] GAD65 antigen therapy in recently diagnosed type 1 diabetes mellitus. (2012). https://pubmed.ncbi.nlm.nih.gov/22296077/ DOI: 10.1056/nejmoa1107096

    Complete structured claim and evidence

30. Chronic treatment with L. rhamnosus JB-1 induced region-dependent alterations in GABA-B1b messenger RNA in the brain with increases in cortical regions and concomitant reductions in expression in the hippocampus, amygdala and locus coeruleus compared with control-fed mice, the strain reduced stress-induced corticosterone and anxiety- and depression-related behavior, and the neurochemical and behavioral effects were not found in vagotomized mice, identifying the vagus as a major modulatory constitutive communication pathway between the bacteria exposed to the gut and the brain.

    Lactobacillus rhamnosus JB-1 → Brain GABA-B receptor subunit 1b messenger RNA expression source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/21876150.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "0008d58bc1bdc0cafce716c1ec3bf74e4bb7a74df49ccec93dafe087aee1183f", "start_char": 0, "end_char": 1706, "text_sha256": "0008d58bc1bdc0cafce716c1ec3bf74e4bb7a74df49ccec93dafe087aee1183f"}

    experimental_model

    Chronic feeding of a single bacterial strain with regional brain receptor expression, behaviour and vagotomy

    exposure

    Chronic Lactobacillus rhamnosus JB-1 in normal healthy mice, with and without vagotomy

    limitations

    The vagotomy arm is what localises the route. It is a single strain in one mouse background, and the receptor changes are messenger RNA rather than protein.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    Feeding one bacterium changed behaviour and brain receptors, and cutting the nerve from gut to brain abolished it.

    primary_references

    [gb-p21876150] Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. (2011). https://pubmed.ncbi.nlm.nih.gov/21876150/ DOI: 10.1073/pnas.1102999108

    tissue_or_cell_type

    Brain, gut and vagus nerve

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 469–480

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Chronic feeding of a single bacterial strain with regional brain receptor expression, behaviour and vagotomy · source_derived_draft · unverified_draft

    ### gb-the-effect-travels-by-nerve Chronic treatment with L. rhamnosus JB-1 induced region-dependent alterations in GABA-B1b messenger RNA in the brain with increases in cortical regions and concomitant reductions in expression in the hippocampus, amygdala and locus coeruleus compared with control-fed mice, the strain reduced stress-induced corticosterone and anxiety- and depression-related behavior, and the neurochemical and behavioral effects were not found in vagotomized mice, identifying the vagus as a major modulatory constitutive communication pathway between the bacteria exposed to the gut and the brain. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Feeding one bacterium changed behaviour and brain receptors, and cutting the nerve from gut to brain abolished it. organism: Mouse tissue_or_cell_type: Brain, gut and vagus nerve experimental_model: Chronic feeding of a single bacterial strain with regional brain receptor expression, behaviour and vagotomy limitations: The vagotomy arm is what localises the route. It is a single strain in one mouse background, and the receptor changes are messenger RNA rather than protein. exposure: Chronic Lactobacillus rhamnosus JB-1 in normal healthy mice, with and without vagotomy evidence_span: {"source_cache": "artifacts/gaba-research/21876150.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "0008d58bc1bdc0cafce716c1ec3bf74e4bb7a74df49ccec93dafe087aee1183f", "start_char": 0, "end_char": 1706, "text_sha256": "0008d58bc1bdc0cafce716c1ec3bf74e4bb7a74df49ccec93dafe087aee1183f"} [gb-p21876150] Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. (2011). https://pubmed.ncbi.nlm.nih.gov/21876150/ DOI: 10.1073/pnas.1102999108

    Complete structured claim and evidence

31. In an 8-week randomized placebo-controlled cross-over design with 29 healthy male volunteers there was no overall effect of probiotic treatment on measures of mood, anxiety, stress or sleep quality and no significant effect over placebo on subjective stress measures or the hypothalamic-pituitary-adrenal response to a socially evaluated cold pressor test, visuospatial memory performance, attention switching, rapid visual information processing, emotion recognition and associated electroencephalographic measures did not show improvement over placebo, and no significant anti-inflammatory effects were seen as assessed by basal and stimulated cytokine levels.

    Lactobacillus rhamnosus JB-1 → Self-reported stress, cognition and HPA response in healthy volunteers source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/27865949.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e575c804cff60d6e87ab46520788fa3619705071562c2c39ff2b6ea57d5552b2", "start_char": 0, "end_char": 2278, "text_sha256": "e575c804cff60d6e87ab46520788fa3619705071562c2c39ff2b6ea57d5552b2"}

    experimental_model

    Randomised placebo-controlled cross-over trial over eight weeks in healthy male volunteers

    exposure

    The same Lactobacillus rhamnosus JB-1 strain against placebo, with a socially evaluated cold pressor test

    limitations

    Twenty-nine healthy men, which is the population most likely to show nothing. The authors state the limitation and call for study in people with stress-related disorders.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Human

    plain_language

    The same bacterium given to healthy men changed nothing that was measured.

    primary_references

    [gb-p27865949] Lost in translation? The potential psychobiotic Lactobacillus rhamnosus (JB-1) fails to modulate stress or cognitive performance in healthy male subjects. (2017). https://pubmed.ncbi.nlm.nih.gov/27865949/ DOI: 10.1016/j.bbi.2016.11.018

    tissue_or_cell_type

    Behaviour, cortisol, cytokines and electroencephalography

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 482–493

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomised placebo-controlled cross-over trial over eight weeks in healthy male volunteers · source_derived_draft · unverified_draft

    ### gb-it-did-not-translate In an 8-week randomized placebo-controlled cross-over design with 29 healthy male volunteers there was no overall effect of probiotic treatment on measures of mood, anxiety, stress or sleep quality and no significant effect over placebo on subjective stress measures or the hypothalamic-pituitary-adrenal response to a socially evaluated cold pressor test, visuospatial memory performance, attention switching, rapid visual information processing, emotion recognition and associated electroencephalographic measures did not show improvement over placebo, and no significant anti-inflammatory effects were seen as assessed by basal and stimulated cytokine levels. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The same bacterium given to healthy men changed nothing that was measured. organism: Human tissue_or_cell_type: Behaviour, cortisol, cytokines and electroencephalography experimental_model: Randomised placebo-controlled cross-over trial over eight weeks in healthy male volunteers limitations: Twenty-nine healthy men, which is the population most likely to show nothing. The authors state the limitation and call for study in people with stress-related disorders. exposure: The same Lactobacillus rhamnosus JB-1 strain against placebo, with a socially evaluated cold pressor test evidence_span: {"source_cache": "artifacts/gaba-research/27865949.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e575c804cff60d6e87ab46520788fa3619705071562c2c39ff2b6ea57d5552b2", "start_char": 0, "end_char": 2278, "text_sha256": "e575c804cff60d6e87ab46520788fa3619705071562c2c39ff2b6ea57d5552b2"} [gb-p27865949] Lost in translation? The potential psychobiotic Lactobacillus rhamnosus (JB-1) fails to modulate stress or cognitive performance in healthy male subjects. (2017). https://pubmed.ncbi.nlm.nih.gov/27865949/ DOI: 10.1016/j.bbi.2016.11.018

    Complete structured claim and evidence

32. Co-culture was used to isolate KLE1738 which required the presence of Bacteroides fragilis to grow, bioassay-driven purification of the supernatant led to isolation of the growth factor which surprisingly is the major inhibitory neurotransmitter GABA, GABA was the only tested nutrient that supported the growth of KLE1738, a variety of GABA-producing bacteria were isolated and Bacteroides species produced large quantities of GABA, transcriptome analysis of human stool from healthy individuals showed that GABA-producing pathways are actively expressed by Bacteroides, Parabacteroides and Escherichia species, and relative abundance levels of faecal Bacteroides are negatively correlated with brain signatures associated with depression.

    Bacteroides fragilis → Gamma-aminobutyric acid source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/30531975.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "c5ec17a6d5ab61a71d407f753583383c556fb07e10434eb3a3c7b42e4d0953f9", "start_char": 0, "end_char": 1773, "text_sha256": "c5ec17a6d5ab61a71d407f753583383c556fb07e10434eb3a3c7b42e4d0953f9"}

    experimental_model

    Co-culture isolation with bioassay-driven purification, genome-based metabolic modelling, stool transcriptomics and brain imaging

    exposure

    A gut isolate that grows only in the presence of another species, and the growth factor it requires

    limitations

    The correlation with depression imaging is observational and the causal direction is not established. The bacteriology is direct.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Human

    plain_language

    One gut bacterium cannot grow without this molecule and another makes it in quantity, and the human gut expresses both halves.

    primary_references

    [gb-p30531975] GABA-modulating bacteria of the human gut microbiota. (2019). https://pubmed.ncbi.nlm.nih.gov/30531975/ DOI: 10.1038/s41564-018-0307-3

    tissue_or_cell_type

    Gut microbiota and brain

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 495–506

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Co-culture isolation with bioassay-driven purification, genome-based metabolic modelling, stool transcriptomics and brain imaging · source_derived_draft · unverified_draft

    ### gb-gut-bacteria-make-and-consume-gaba Co-culture was used to isolate KLE1738 which required the presence of Bacteroides fragilis to grow, bioassay-driven purification of the supernatant led to isolation of the growth factor which surprisingly is the major inhibitory neurotransmitter GABA, GABA was the only tested nutrient that supported the growth of KLE1738, a variety of GABA-producing bacteria were isolated and Bacteroides species produced large quantities of GABA, transcriptome analysis of human stool from healthy individuals showed that GABA-producing pathways are actively expressed by Bacteroides, Parabacteroides and Escherichia species, and relative abundance levels of faecal Bacteroides are negatively correlated with brain signatures associated with depression. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: One gut bacterium cannot grow without this molecule and another makes it in quantity, and the human gut expresses both halves. organism: Human tissue_or_cell_type: Gut microbiota and brain experimental_model: Co-culture isolation with bioassay-driven purification, genome-based metabolic modelling, stool transcriptomics and brain imaging limitations: The correlation with depression imaging is observational and the causal direction is not established. The bacteriology is direct. exposure: A gut isolate that grows only in the presence of another species, and the growth factor it requires evidence_span: {"source_cache": "artifacts/gaba-research/30531975.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "c5ec17a6d5ab61a71d407f753583383c556fb07e10434eb3a3c7b42e4d0953f9", "start_char": 0, "end_char": 1773, "text_sha256": "c5ec17a6d5ab61a71d407f753583383c556fb07e10434eb3a3c7b42e4d0953f9"} [gb-p30531975] GABA-modulating bacteria of the human gut microbiota. (2019). https://pubmed.ncbi.nlm.nih.gov/30531975/ DOI: 10.1038/s41564-018-0307-3

    Complete structured claim and evidence

33. We examined in encephalitogenic T cells if they expressed functional GABA channels that could be activated by the low nanomolar to 1 micromolar physiological concentrations of GABA present around neurons in the brain, the cells expressed the alpha1, alpha4, beta2, beta3, gamma1 and delta GABA-A channel subunits and formed functional extrasynaptic-like GABA channels that were activated by 1 micromolar GABA, and 100 nanomolar and higher GABA concentrations decreased T cell proliferation.

    Gamma-aminobutyric acid → T-cell proliferation, model specified source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/18954912.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3723b5b4b643817af252230d67dafbc0b5ca2deadb17cdbdbc9f340ddfc6a472", "start_char": 0, "end_char": 728, "text_sha256": "3723b5b4b643817af252230d67dafbc0b5ca2deadb17cdbdbc9f340ddfc6a472"}

    experimental_model

    Patch clamp and proliferation assays on encephalitogenic T cells at physiological GABA concentrations

    exposure

    GABA at nanomolar to micromolar concentrations, the range present around neurons

    limitations

    A small subunit and function study in one T cell type. It measures the concentration range that matters rather than assuming it.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Rat

    plain_language

    These cells carry the kind of channel built for a steady background level rather than a synaptic pulse, and that background level slows them down.

    primary_references

    [gb-p18954912] GABA, a natural immunomodulator of T lymphocytes. (2008). https://pubmed.ncbi.nlm.nih.gov/18954912/ DOI: 10.1016/j.jneuroim.2008.08.017

    tissue_or_cell_type

    Encephalitogenic T cell

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 508–519

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Patch clamp and proliferation assays on encephalitogenic T cells at physiological GABA concentrations · source_derived_draft · unverified_draft

    ### gb-t-cells-read-ambient-gaba We examined in encephalitogenic T cells if they expressed functional GABA channels that could be activated by the low nanomolar to 1 micromolar physiological concentrations of GABA present around neurons in the brain, the cells expressed the alpha1, alpha4, beta2, beta3, gamma1 and delta GABA-A channel subunits and formed functional extrasynaptic-like GABA channels that were activated by 1 micromolar GABA, and 100 nanomolar and higher GABA concentrations decreased T cell proliferation. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: These cells carry the kind of channel built for a steady background level rather than a synaptic pulse, and that background level slows them down. organism: Rat tissue_or_cell_type: Encephalitogenic T cell experimental_model: Patch clamp and proliferation assays on encephalitogenic T cells at physiological GABA concentrations limitations: A small subunit and function study in one T cell type. It measures the concentration range that matters rather than assuming it. exposure: GABA at nanomolar to micromolar concentrations, the range present around neurons evidence_span: {"source_cache": "artifacts/gaba-research/18954912.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "3723b5b4b643817af252230d67dafbc0b5ca2deadb17cdbdbc9f340ddfc6a472", "start_char": 0, "end_char": 728, "text_sha256": "3723b5b4b643817af252230d67dafbc0b5ca2deadb17cdbdbc9f340ddfc6a472"} [gb-p18954912] GABA, a natural immunomodulator of T lymphocytes. (2008). https://pubmed.ncbi.nlm.nih.gov/18954912/ DOI: 10.1016/j.jneuroim.2008.08.017

    Complete structured claim and evidence

34. There were 5, 8 and 13 different GABA-A subunit isoforms identified in human, mouse and rat CD4-positive and CD8-positive T cells respectively, importantly the gamma2 subunit that imposes benzodiazepine sensitivity on the GABA-A receptors was only detected in the mouse T cells, immunoblots and immunocytochemistry showed abundant GABA-A channel proteins in T cells from all three species, GABA-activated whole-cell transient and tonic currents were recorded and were inhibited by picrotoxin, SR95531 and bicuculline, and it is important to bear in mind the interspecies difference when selecting the appropriate animal models and when selecting drugs aimed at modulating human T cell function.

    The GABA-A receptor subunit repertoire of a cell → GABA-A receptor anion channels source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/22927941.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "0457001832d2a3595899415221b7797f5288a787c1d52fd6afa1acf24f032402", "start_char": 0, "end_char": 1589, "text_sha256": "0457001832d2a3595899415221b7797f5288a787c1d52fd6afa1acf24f032402"}

    experimental_model

    Subunit isoform survey with immunoblotting, immunocytochemistry and whole-cell recording across three species

    exposure

    GABA-activated transient and tonic currents, with picrotoxin, SR95531 and bicuculline

    limitations

    The species comparison is the point. Subunit repertoires differ enough that a drug result in one species does not carry to another.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Human, mouse and rat

    plain_language

    The subunit that makes a receptor respond to benzodiazepines was found on mouse T cells and not on human ones.

    primary_references

    [gb-p22927941] Different subtypes of GABA-A receptors are expressed in human, mouse and rat T lymphocytes. (2012). https://pubmed.ncbi.nlm.nih.gov/22927941/ DOI: 10.1371/journal.pone.0042959

    tissue_or_cell_type

    CD4 and CD8 T lymphocytes

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 521–532

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Subunit isoform survey with immunoblotting, immunocytochemistry and whole-cell recording across three species · source_derived_draft · unverified_draft

    ### gb-the-subunits-differ-by-species There were 5, 8 and 13 different GABA-A subunit isoforms identified in human, mouse and rat CD4-positive and CD8-positive T cells respectively, importantly the gamma2 subunit that imposes benzodiazepine sensitivity on the GABA-A receptors was only detected in the mouse T cells, immunoblots and immunocytochemistry showed abundant GABA-A channel proteins in T cells from all three species, GABA-activated whole-cell transient and tonic currents were recorded and were inhibited by picrotoxin, SR95531 and bicuculline, and it is important to bear in mind the interspecies difference when selecting the appropriate animal models and when selecting drugs aimed at modulating human T cell function. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The subunit that makes a receptor respond to benzodiazepines was found on mouse T cells and not on human ones. organism: Human, mouse and rat tissue_or_cell_type: CD4 and CD8 T lymphocytes experimental_model: Subunit isoform survey with immunoblotting, immunocytochemistry and whole-cell recording across three species limitations: The species comparison is the point. Subunit repertoires differ enough that a drug result in one species does not carry to another. exposure: GABA-activated transient and tonic currents, with picrotoxin, SR95531 and bicuculline evidence_span: {"source_cache": "artifacts/gaba-research/22927941.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "0457001832d2a3595899415221b7797f5288a787c1d52fd6afa1acf24f032402", "start_char": 0, "end_char": 1589, "text_sha256": "0457001832d2a3595899415221b7797f5288a787c1d52fd6afa1acf24f032402"} [gb-p22927941] Different subtypes of GABA-A receptors are expressed in human, mouse and rat T lymphocytes. (2012). https://pubmed.ncbi.nlm.nih.gov/22927941/ DOI: 10.1371/journal.pone.0042959

    Complete structured claim and evidence

35. A subset of GABA-A receptor subunits are expressed by CD4-positive T cells including the delta subunit that confers high affinity for GABA and sensitivity to alcohol, GABA at relatively low concentrations down-regulated effector T cell responses to beta cell antigens ex vivo and administration of GABA retarded the adoptive transfer of type 1 diabetes in NOD/scid mice, treatment with a low dose of GABA at 600 micrograms daily dramatically inhibited the development of proinflammatory T cell responses and disease progression in disease-prone mice that already had established autoimmunity, and GABA inhibited T cell receptor-mediated T cell cycle progression in vitro which may underlie the therapeutic effects.

    Gamma-aminobutyric acid → Type 1 diabetes source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/15470076.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e5523c02fc4571d5ab6c23776794b4b5cf025fb86cdba9acdc12011f3a6b2e09", "start_char": 0, "end_char": 1443, "text_sha256": "e5523c02fc4571d5ab6c23776794b4b5cf025fb86cdba9acdc12011f3a6b2e09"}

    experimental_model

    Subunit analysis with ex vivo antigen responses, adoptive transfer and treatment of disease-prone mice

    exposure

    GABA at low concentrations ex vivo, and 600 micrograms daily in mice with established autoimmunity

    limitations

    A mouse type 1 diabetes model. The cell cycle result offers a mechanism for the disease effect but is measured separately from it.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    Low doses slowed the immune attack on the insulin-producing cells even after that attack had already started.

    primary_references

    [gb-p15470076] Gamma-aminobutyric acid inhibits T cell autoimmunity and the development of inflammatory responses in a mouse type 1 diabetes model. (2004). https://pubmed.ncbi.nlm.nih.gov/15470076/ DOI: 10.4049/jimmunol.173.8.5298

    tissue_or_cell_type

    CD4 T cell and pancreatic islet

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 534–545

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Subunit analysis with ex vivo antigen responses, adoptive transfer and treatment of disease-prone mice · source_derived_draft · unverified_draft

    ### gb-gaba-slows-the-autoimmune-t-cell A subset of GABA-A receptor subunits are expressed by CD4-positive T cells including the delta subunit that confers high affinity for GABA and sensitivity to alcohol, GABA at relatively low concentrations down-regulated effector T cell responses to beta cell antigens ex vivo and administration of GABA retarded the adoptive transfer of type 1 diabetes in NOD/scid mice, treatment with a low dose of GABA at 600 micrograms daily dramatically inhibited the development of proinflammatory T cell responses and disease progression in disease-prone mice that already had established autoimmunity, and GABA inhibited T cell receptor-mediated T cell cycle progression in vitro which may underlie the therapeutic effects. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Low doses slowed the immune attack on the insulin-producing cells even after that attack had already started. organism: Mouse tissue_or_cell_type: CD4 T cell and pancreatic islet experimental_model: Subunit analysis with ex vivo antigen responses, adoptive transfer and treatment of disease-prone mice limitations: A mouse type 1 diabetes model. The cell cycle result offers a mechanism for the disease effect but is measured separately from it. exposure: GABA at low concentrations ex vivo, and 600 micrograms daily in mice with established autoimmunity evidence_span: {"source_cache": "artifacts/gaba-research/15470076.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e5523c02fc4571d5ab6c23776794b4b5cf025fb86cdba9acdc12011f3a6b2e09", "start_char": 0, "end_char": 1443, "text_sha256": "e5523c02fc4571d5ab6c23776794b4b5cf025fb86cdba9acdc12011f3a6b2e09"} [gb-p15470076] Gamma-aminobutyric acid inhibits T cell autoimmunity and the development of inflammatory responses in a mouse type 1 diabetes model. (2004). https://pubmed.ncbi.nlm.nih.gov/15470076/ DOI: 10.4049/jimmunol.173.8.5298

    Complete structured claim and evidence

36. Immune cells synthesize GABA and have the machinery for GABA catabolism, antigen-presenting cells express functional GABA receptors and respond electrophysiologically to GABA, thus the immune system harbors all of the necessary constituents for GABA signaling and GABA itself may function as a paracrine or autocrine factor, increasing GABAergic activity ameliorates ongoing paralysis in experimental autoimmune encephalomyelitis via inhibition of inflammation, and GABAergic agents act directly on antigen-presenting cells decreasing MAPK signals and diminishing subsequent adaptive inflammatory responses to myelin proteins.

    Antigen-presenting cell → Gamma-aminobutyric acid source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/20133656.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "15fc62882eb9a9c1f5daad1bd2845bc99c94f1cf076620badc55b6be390e35fd", "start_char": 0, "end_char": 896, "text_sha256": "15fc62882eb9a9c1f5daad1bd2845bc99c94f1cf076620badc55b6be390e35fd"}

    experimental_model

    Demonstration of GABA synthesis and catabolism machinery in immune cells with electrophysiology and an autoimmune disease model

    exposure

    Increasing GABAergic activity in established experimental autoimmune encephalomyelitis

    limitations

    The disease effect is on ongoing paralysis rather than prevention. The assignment to antigen-presenting cells rests on direct effects measured on those cells.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    The immune system has the whole apparatus to make and break down this transmitter, and uses it on itself.

    primary_references

    [gb-p20133656] Inhibitory role for GABA in autoimmune inflammation. (2010). https://pubmed.ncbi.nlm.nih.gov/20133656/ DOI: 10.1073/pnas.0915139107

    tissue_or_cell_type

    Antigen-presenting cell and central nervous system

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 547–558

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Demonstration of GABA synthesis and catabolism machinery in immune cells with electrophysiology and an autoimmune disease model · source_derived_draft · unverified_draft

    ### gb-immune-cells-make-their-own-gaba Immune cells synthesize GABA and have the machinery for GABA catabolism, antigen-presenting cells express functional GABA receptors and respond electrophysiologically to GABA, thus the immune system harbors all of the necessary constituents for GABA signaling and GABA itself may function as a paracrine or autocrine factor, increasing GABAergic activity ameliorates ongoing paralysis in experimental autoimmune encephalomyelitis via inhibition of inflammation, and GABAergic agents act directly on antigen-presenting cells decreasing MAPK signals and diminishing subsequent adaptive inflammatory responses to myelin proteins. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The immune system has the whole apparatus to make and break down this transmitter, and uses it on itself. organism: Mouse tissue_or_cell_type: Antigen-presenting cell and central nervous system experimental_model: Demonstration of GABA synthesis and catabolism machinery in immune cells with electrophysiology and an autoimmune disease model limitations: The disease effect is on ongoing paralysis rather than prevention. The assignment to antigen-presenting cells rests on direct effects measured on those cells. exposure: Increasing GABAergic activity in established experimental autoimmune encephalomyelitis evidence_span: {"source_cache": "artifacts/gaba-research/20133656.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "15fc62882eb9a9c1f5daad1bd2845bc99c94f1cf076620badc55b6be390e35fd", "start_char": 0, "end_char": 896, "text_sha256": "15fc62882eb9a9c1f5daad1bd2845bc99c94f1cf076620badc55b6be390e35fd"} [gb-p20133656] Inhibitory role for GABA in autoimmune inflammation. (2010). https://pubmed.ncbi.nlm.nih.gov/20133656/ DOI: 10.1073/pnas.0915139107

    Complete structured claim and evidence

37. GABA transporter GAT2 modulates macrophage function and GAT2 deficiency lowers the production of interleukin-1 beta in proinflammatory macrophages, mechanistically GAT2 deficiency boosts the betaine, S-adenosylmethionine and hypoxanthine metabolic pathway to inhibit transcription factor KID3 expression through increased DNA methylation in its promoter region, KID3 regulates oxidative phosphorylation via targeting the expression of related genes and is also critical for NLRP3-ASC-caspase-1 complex formation, and GAT2 deficiency attenuates macrophage-mediated inflammatory responses in vivo including lipopolysaccharide-induced sepsis, infection-induced pneumonia and high-fat diet-induced obesity.

    The GABA transporter GAT2 → Interleukin-1 beta / IL1B source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/33827820.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7c654d761170222f117b179e232f555803d6a7cadcfb2eed7b95c45539787cff", "start_char": 0, "end_char": 1140, "text_sha256": "7c654d761170222f117b179e232f555803d6a7cadcfb2eed7b95c45539787cff"}

    experimental_model

    Transporter deficiency with metabolic pathway analysis, promoter methylation and three in vivo inflammatory models

    exposure

    GAT2 deficiency in macrophages, with lipopolysaccharide sepsis, infection-induced pneumonia and high-fat diet models

    limitations

    The mechanism assigned here is metabolic and transcriptional, running through methylation of a transcription factor promoter, rather than an electrophysiological one.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    Taking away the carrier that moves GABA into the macrophage lowered its main inflammatory output, through a metabolic route and not an electrical one.

    primary_references

    [gb-p33827820] GABA transporter sustains IL-1β production in macrophages. (2021). https://pubmed.ncbi.nlm.nih.gov/33827820/ DOI: 10.1126/sciadv.abe9274

    tissue_or_cell_type

    Proinflammatory macrophage

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 560–571

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Transporter deficiency with metabolic pathway analysis, promoter methylation and three in vivo inflammatory models · source_derived_draft · unverified_draft

    ### gb-the-transporter-sustains-il1b GABA transporter GAT2 modulates macrophage function and GAT2 deficiency lowers the production of interleukin-1 beta in proinflammatory macrophages, mechanistically GAT2 deficiency boosts the betaine, S-adenosylmethionine and hypoxanthine metabolic pathway to inhibit transcription factor KID3 expression through increased DNA methylation in its promoter region, KID3 regulates oxidative phosphorylation via targeting the expression of related genes and is also critical for NLRP3-ASC-caspase-1 complex formation, and GAT2 deficiency attenuates macrophage-mediated inflammatory responses in vivo including lipopolysaccharide-induced sepsis, infection-induced pneumonia and high-fat diet-induced obesity. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Taking away the carrier that moves GABA into the macrophage lowered its main inflammatory output, through a metabolic route and not an electrical one. organism: Mouse tissue_or_cell_type: Proinflammatory macrophage experimental_model: Transporter deficiency with metabolic pathway analysis, promoter methylation and three in vivo inflammatory models limitations: The mechanism assigned here is metabolic and transcriptional, running through methylation of a transcription factor promoter, rather than an electrophysiological one. exposure: GAT2 deficiency in macrophages, with lipopolysaccharide sepsis, infection-induced pneumonia and high-fat diet models evidence_span: {"source_cache": "artifacts/gaba-research/33827820.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7c654d761170222f117b179e232f555803d6a7cadcfb2eed7b95c45539787cff", "start_char": 0, "end_char": 1140, "text_sha256": "7c654d761170222f117b179e232f555803d6a7cadcfb2eed7b95c45539787cff"} [gb-p33827820] GABA transporter sustains IL-1β production in macrophages. (2021). https://pubmed.ncbi.nlm.nih.gov/33827820/ DOI: 10.1126/sciadv.abe9274

    Complete structured claim and evidence

38. GABA-A receptor subunits were expressed by primary lung macrophages of mice and the mouse macrophage cell line RAW264.7, the expression levels of these subunits decreased or increased concurrently with classical M1 or alternative M2 activation respectively, moreover activation or blockade of the receptors distinctively influenced the phenotypic characteristics of the macrophages, and these results suggested that microenvironments leading to macrophage phenotypic polarization concurrently modulate autocrine GABA signaling and its role in macrophage activation.

    Classical M1-like and alternative M2-like macrophage activation → GABA-A receptor anion channels source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/30017085.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8c2d49008808726bf766218eb51ab5ec08e9790897619e750b8caacc1afad63b", "start_char": 0, "end_char": 1120, "text_sha256": "8c2d49008808726bf766218eb51ab5ec08e9790897619e750b8caacc1afad63b"}

    experimental_model

    Subunit expression and phenotype in primary lung macrophages and a macrophage cell line under polarising conditions

    exposure

    Classical and alternative activating conditions, with GABA-A receptor activation or blockade

    limitations

    Expression changes and phenotype rather than disease outcome. It shows the receptor tracks polarisation rather than that it drives it.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    The receptor goes up as the cell takes the repair-type phenotype and down as it takes the inflammatory one.

    primary_references

    [gb-p30017085] Autocrine GABA signaling distinctively regulates phenotypic activation of mouse pulmonary macrophages. (2018). https://pubmed.ncbi.nlm.nih.gov/30017085/ DOI: 10.1016/j.cellimm.2018.07.001

    tissue_or_cell_type

    Lung macrophage

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 573–584

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Subunit expression and phenotype in primary lung macrophages and a macrophage cell line under polarising conditions · source_derived_draft · unverified_draft

    ### gb-the-receptor-tracks-polarisation GABA-A receptor subunits were expressed by primary lung macrophages of mice and the mouse macrophage cell line RAW264.7, the expression levels of these subunits decreased or increased concurrently with classical M1 or alternative M2 activation respectively, moreover activation or blockade of the receptors distinctively influenced the phenotypic characteristics of the macrophages, and these results suggested that microenvironments leading to macrophage phenotypic polarization concurrently modulate autocrine GABA signaling and its role in macrophage activation. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The receptor goes up as the cell takes the repair-type phenotype and down as it takes the inflammatory one. organism: Mouse tissue_or_cell_type: Lung macrophage experimental_model: Subunit expression and phenotype in primary lung macrophages and a macrophage cell line under polarising conditions limitations: Expression changes and phenotype rather than disease outcome. It shows the receptor tracks polarisation rather than that it drives it. exposure: Classical and alternative activating conditions, with GABA-A receptor activation or blockade evidence_span: {"source_cache": "artifacts/gaba-research/30017085.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8c2d49008808726bf766218eb51ab5ec08e9790897619e750b8caacc1afad63b", "start_char": 0, "end_char": 1120, "text_sha256": "8c2d49008808726bf766218eb51ab5ec08e9790897619e750b8caacc1afad63b"} [gb-p30017085] Autocrine GABA signaling distinctively regulates phenotypic activation of mouse pulmonary macrophages. (2018). https://pubmed.ncbi.nlm.nih.gov/30017085/ DOI: 10.1016/j.cellimm.2018.07.001

    Complete structured claim and evidence

39. Intracellular bacterial infection decreases GABA levels in vitro in macrophages and in vivo in sera, treatment of macrophages with GABA or GABAergic drugs promotes autophagy activation, enhances phagosomal maturation and antimicrobial responses against mycobacterial infection, in macrophages the GABAergic defense is mediated via macrophage type A GABA receptor, intracellular calcium release and the GABA type A receptor-associated protein-like 1, and GABAergic inhibition increases bacterial loads in mice and zebrafish in vivo suggesting that the GABAergic defense plays an essential function in metazoan host defenses.

    Gamma-aminobutyric acid → Autophagy activation source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/30305619.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4d53b15743f61b910fb1db4781905673c81a070c12245068a369548544e3bc6e", "start_char": 0, "end_char": 1146, "text_sha256": "4d53b15743f61b910fb1db4781905673c81a070c12245068a369548544e3bc6e"}

    experimental_model

    Autophagy and phagosome assays in macrophages with receptor and protein dependency, and infection burden in two whole animals

    exposure

    GABA and GABAergic drugs during intracellular mycobacterial infection, with GABAergic inhibition in vivo

    limitations

    The dependency on the receptor and on a specific autophagy protein is tested, and the outcome is measured in two species. The direction is the opposite of the autoimmunity records.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse and zebrafish

    plain_language

    Here the same molecule helps rather than suppresses: it drives the cell to digest the bacteria inside it, and blocking it lets the infection grow.

    primary_references

    [gb-p30305619] GABAergic signaling linked to autophagy enhances host protection against intracellular bacterial infections. (2018). https://pubmed.ncbi.nlm.nih.gov/30305619/ DOI: 10.1038/s41467-018-06487-5

    tissue_or_cell_type

    Macrophage

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 586–597

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Autophagy and phagosome assays in macrophages with receptor and protein dependency, and infection burden in two whole animals · source_derived_draft · unverified_draft

    ### gb-gaba-helps-the-host-kill-bacteria Intracellular bacterial infection decreases GABA levels in vitro in macrophages and in vivo in sera, treatment of macrophages with GABA or GABAergic drugs promotes autophagy activation, enhances phagosomal maturation and antimicrobial responses against mycobacterial infection, in macrophages the GABAergic defense is mediated via macrophage type A GABA receptor, intracellular calcium release and the GABA type A receptor-associated protein-like 1, and GABAergic inhibition increases bacterial loads in mice and zebrafish in vivo suggesting that the GABAergic defense plays an essential function in metazoan host defenses. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: Here the same molecule helps rather than suppresses: it drives the cell to digest the bacteria inside it, and blocking it lets the infection grow. organism: Mouse and zebrafish tissue_or_cell_type: Macrophage experimental_model: Autophagy and phagosome assays in macrophages with receptor and protein dependency, and infection burden in two whole animals limitations: The dependency on the receptor and on a specific autophagy protein is tested, and the outcome is measured in two species. The direction is the opposite of the autoimmunity records. exposure: GABA and GABAergic drugs during intracellular mycobacterial infection, with GABAergic inhibition in vivo evidence_span: {"source_cache": "artifacts/gaba-research/30305619.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4d53b15743f61b910fb1db4781905673c81a070c12245068a369548544e3bc6e", "start_char": 0, "end_char": 1146, "text_sha256": "4d53b15743f61b910fb1db4781905673c81a070c12245068a369548544e3bc6e"} [gb-p30305619] GABAergic signaling linked to autophagy enhances host protection against intracellular bacterial infections. (2018). https://pubmed.ncbi.nlm.nih.gov/30305619/ DOI: 10.1038/s41467-018-06487-5

    Complete structured claim and evidence

40. We identify the metabolite and neurotransmitter GABA as a candidate signalling molecule synthesized and secreted by activated B cells and plasma cells, B cell-derived GABA promotes monocyte differentiation into anti-inflammatory macrophages that secrete interleukin-10 and inhibit CD8-positive T cell killer function, and in mice B cell deficiency or B cell-specific inactivation of the GABA-generating enzyme GAD67 enhances anti-tumour responses.

    B cell → Gamma-aminobutyric acid source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/34732892.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "907d2a95afcac30a55ebfa4a6056c31ca53c452caff350ded70a60c9fc2eb17b", "start_char": 0, "end_char": 878, "text_sha256": "907d2a95afcac30a55ebfa4a6056c31ca53c452caff350ded70a60c9fc2eb17b"}

    experimental_model

    Identification of a metabolite secreted by activated B cells, with monocyte differentiation and two genetic tests in mice

    exposure

    B cell-derived GABA, with B cell deficiency and B cell-specific inactivation of the GABA-generating enzyme GAD67

    limitations

    The B cell-specific enzyme deletion is what makes the source assignment strong. The enzyme deleted is GAD67, not the GAD65 that is the diabetes autoantigen.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse

    plain_language

    B cells release this molecule into a tumour, where it turns arriving monocytes into cells that shut down the killers.

    primary_references

    [gb-p34732892] B cell-derived GABA elicits IL-10+ macrophages to limit anti-tumour immunity. (2021). https://pubmed.ncbi.nlm.nih.gov/34732892/ DOI: 10.1038/s41586-021-04082-1

    tissue_or_cell_type

    B cell, monocyte and tumour

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 599–610

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Identification of a metabolite secreted by activated B cells, with monocyte differentiation and two genetic tests in mice · source_derived_draft · unverified_draft

    ### gb-b-cells-secrete-gaba-that-shields-tumours We identify the metabolite and neurotransmitter GABA as a candidate signalling molecule synthesized and secreted by activated B cells and plasma cells, B cell-derived GABA promotes monocyte differentiation into anti-inflammatory macrophages that secrete interleukin-10 and inhibit CD8-positive T cell killer function, and in mice B cell deficiency or B cell-specific inactivation of the GABA-generating enzyme GAD67 enhances anti-tumour responses. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: B cells release this molecule into a tumour, where it turns arriving monocytes into cells that shut down the killers. organism: Mouse tissue_or_cell_type: B cell, monocyte and tumour experimental_model: Identification of a metabolite secreted by activated B cells, with monocyte differentiation and two genetic tests in mice limitations: The B cell-specific enzyme deletion is what makes the source assignment strong. The enzyme deleted is GAD67, not the GAD65 that is the diabetes autoantigen. exposure: B cell-derived GABA, with B cell deficiency and B cell-specific inactivation of the GABA-generating enzyme GAD67 evidence_span: {"source_cache": "artifacts/gaba-research/34732892.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "907d2a95afcac30a55ebfa4a6056c31ca53c452caff350ded70a60c9fc2eb17b", "start_char": 0, "end_char": 878, "text_sha256": "907d2a95afcac30a55ebfa4a6056c31ca53c452caff350ded70a60c9fc2eb17b"} [gb-p34732892] B cell-derived GABA elicits IL-10+ macrophages to limit anti-tumour immunity. (2021). https://pubmed.ncbi.nlm.nih.gov/34732892/ DOI: 10.1038/s41586-021-04082-1

    Complete structured claim and evidence

41. Necrosis releases intracellular potassium ions into the extracellular fluid of mouse and human tumours causing profound suppression of T cell effector function, elevation of the extracellular potassium concentration impairs T cell receptor-driven Akt-mTOR phosphorylation and effector programmes, potassium-mediated suppression of Akt-mTOR signalling and T cell function is dependent upon the activity of the serine/threonine phosphatase PP2A, although the suppressive effect mediated by elevated extracellular potassium is independent of changes in plasma membrane potential it requires an increase in intracellular potassium, and augmenting potassium efflux in tumour-specific T cells by overexpressing the potassium channel Kv1.3 lowers intracellular potassium and improves effector functions in vitro and in vivo.

    Intracellular potassium concentration → TCR-driven Akt-mTOR phosphorylation source_derived_draftungraded
    Experimental context and source evidence

    evidence_span

    {"source_cache": "artifacts/gaba-research/27626381.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "73f83e208d8ad23be6c7ada4127b06536cdfd3156c4ac588e004e775761214f8", "start_char": 0, "end_char": 1240, "text_sha256": "73f83e208d8ad23be6c7ada4127b06536cdfd3156c4ac588e004e775761214f8"}

    experimental_model

    Measurement of potassium released by tumour necrosis with T cell signalling, phosphatase dependency and channel overexpression in melanoma-bearing mice

    exposure

    Elevated extracellular potassium from necrotic tumour areas, with Kv1.3 overexpression in tumour-specific T cells

    limitations

    Included here because it is routinely placed alongside the tumour GABA story. Its own abstract states that the suppression is independent of changes in plasma membrane potential, which is the opposite of what that pairing usually assumes.

    nutrient_topic

    GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. · Gamma-aminobutyric acid

    organism

    Mouse and human

    plain_language

    The tumour potassium that disarms T cells does so by getting inside them and switching on a phosphatase, not by changing the voltage across the membrane.

    primary_references

    [gb-p27626381] Ionic immune suppression within the tumour microenvironment limits T cell effector function. (2016). https://pubmed.ncbi.nlm.nih.gov/27626381/ DOI: 10.1038/nature19364

    tissue_or_cell_type

    Tumour microenvironment and T cell

    GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22) · lines 612–623

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Measurement of potassium released by tumour necrosis with T cell signalling, phosphatase dependency and channel overexpression in melanoma-bearing mice · source_derived_draft · unverified_draft

    ### gb-the-potassium-effect-is-not-electrical Necrosis releases intracellular potassium ions into the extracellular fluid of mouse and human tumours causing profound suppression of T cell effector function, elevation of the extracellular potassium concentration impairs T cell receptor-driven Akt-mTOR phosphorylation and effector programmes, potassium-mediated suppression of Akt-mTOR signalling and T cell function is dependent upon the activity of the serine/threonine phosphatase PP2A, although the suppressive effect mediated by elevated extracellular potassium is independent of changes in plasma membrane potential it requires an increase in intracellular potassium, and augmenting potassium efflux in tumour-specific T cells by overexpressing the potassium channel Kv1.3 lowers intracellular potassium and improves effector functions in vitro and in vivo. Condition category: normal nutrient_topic: GABA research collection; topical membership is not evidence of a direct clinical effect, and the sign of a GABA response depends on the chloride gradient of the cell it was measured in. plain_language: The tumour potassium that disarms T cells does so by getting inside them and switching on a phosphatase, not by changing the voltage across the membrane. organism: Mouse and human tissue_or_cell_type: Tumour microenvironment and T cell experimental_model: Measurement of potassium released by tumour necrosis with T cell signalling, phosphatase dependency and channel overexpression in melanoma-bearing mice limitations: Included here because it is routinely placed alongside the tumour GABA story. Its own abstract states that the suppression is independent of changes in plasma membrane potential, which is the opposite of what that pairing usually assumes. exposure: Elevated extracellular potassium from necrotic tumour areas, with Kv1.3 overexpression in tumour-specific T cells evidence_span: {"source_cache": "artifacts/gaba-research/27626381.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "73f83e208d8ad23be6c7ada4127b06536cdfd3156c4ac588e004e775761214f8", "start_char": 0, "end_char": 1240, "text_sha256": "73f83e208d8ad23be6c7ada4127b06536cdfd3156c4ac588e004e775761214f8"} [gb-p27626381] Ionic immune suppression within the tumour microenvironment limits T cell effector function. (2016). https://pubmed.ncbi.nlm.nih.gov/27626381/ DOI: 10.1038/nature19364

    Complete structured claim and evidence

• GABA: a ligand with no sign of its own, the cofactor that limits its synthesis, the barrier that keeps it out of the brain, and the immune settings where the same molecule protects and harms (2026-09-22)AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · unverified_draftRead preserved source

• Does GABA act directly on the insulin-producing cell?Two studies of the same tissue disagree about whether the receptor is there at all. The rat islet study found GABA-A receptors by immunocytochemistry in glucagon-secreting alpha cells but not in beta or delta cells, detected alpha1, alpha4 and beta1-3 subunit transcripts in purified alpha cells but not in beta cells, and found that blocking the receptor left insulin and somatostatin secretion unaffected while abolishing the glucose effect on glucagon. The mouse therapy study states that GABA depolarises beta cells and drives calcium influx into a survival pathway, which requires a receptor on that cell. Species, method and purpose all differ, and a receptor population too sparse for immunocytochemistry in purified rat cells could still carry a signal in intact mouse islets. Nothing in this collection measures the beta cell chloride gradient, which is what would make the depolarisation claim independently checkable.Read the recorded disagreement
• Does swallowing GABA produce an effect, and if so where?Three lines have to be held together. The barrier records say the molecule is largely kept out of the brain: the carrier at the barrier has a Michaelis constant of 679 micromolar, the brain exports GABA back to blood with a half-time of five to fifteen minutes, and systemic infusion across a thousand-fold dose range raised cerebrospinal fluid GABA only from about 0.5 to 11 micromolar. Against that, a single oral dose shifted the electroencephalogram within an hour in thirteen people, and two placebo-controlled trials found blood pressure reductions. The third line is what decides how much weight the second carries: in the one study that used the same fermented food prepared without GABA as its control, the control lowered blood pressure as well, by 5.5 over 7.6 millimetres of mercury. So an effect of these preparations on blood pressure is reasonably supported and an effect of GABA specifically is not, and any central effect has to be reconciled with a barrier that demonstrably pushes the molecule back out.Read the recorded disagreement
• Is GABA protective or harmful when the immune system is involved?The direction reverses with the setting, and every record here is consistent within its own. In autoimmunity it protects: low concentrations slow effector T cell responses and disease progression in a mouse type 1 diabetes model, and raising GABAergic activity improves ongoing paralysis in an autoimmune model of central nervous system disease by acting on antigen-presenting cells. In intracellular bacterial infection it also protects, but by the opposite kind of action: infection lowers GABA, and giving it drives autophagy and phagosomal maturation so that blocking GABAergic signalling increases bacterial load in two species. In tumours it harms: B cell-derived GABA turns monocytes into interleukin-10-secreting macrophages that shut down CD8 killing, and deleting the enzyme that makes it in B cells improves anti-tumour responses. A macrophage record cuts across all three, since removing the transporter that carries GABA into the cell lowered interleukin-1 beta, which makes GABA uptake pro-inflammatory in that setting rather than anti-inflammatory. What the collection does not contain is any measurement that would let these be reduced to one mechanism with a context-dependent sign.Read the recorded disagreement

• Whether raising GABA helps, does nothing, or harms in a tissue whose chloride gradient has collapsed.The records here establish that GABA-activated currents invert when KCC2 falls, and that this happens in the dorsal horn after nerve injury. It is a short step to predicting that a GABA-A agonist would lose or reverse its effect in that tissue, and that step is not taken by any record in this collection: none of them gave a GABA-A agonist to an animal with a collapsed gradient and measured pain. The prediction is recorded as a question rather than as a finding.
• What the chloride gradient is in a lymphocyte, and therefore which way a GABA-A current runs in one.Every functional record here reports what GABA does to an immune cell without reporting the cell intracellular chloride concentration or the reversal potential of the current. The sign of a GABA-A response is set by that gradient in every neuronal record in this collection, so the same question is the obvious one to ask of a lymphocyte, and no record here answers it. Until it is measured, describing GABA as inhibitory to T cells states the outcome and not the mechanism.
• Whether tumour potassium and tumour GABA suppress T cells through any shared step.They are often grouped as one ionic phenomenon. The potassium study states explicitly that its suppressive effect is independent of changes in plasma membrane potential and requires a rise in intracellular potassium acting through PP2A on Akt-mTOR. The GABA record runs through a different cell entirely, with B cell-derived GABA redirecting monocyte differentiation toward interleukin-10-secreting macrophages. Nothing in this collection measures membrane potential, chloride or PP2A in the same experiment, so a shared electrical mechanism is not supported by these records and is not recorded as one.
• Whether benzodiazepines modulate human immune cells through the receptors measured here.The subunit survey found the gamma2 subunit that confers benzodiazepine sensitivity on mouse T cells and not on human ones, which means a benzodiazepine effect demonstrated on mouse lymphocytes cannot be carried across to people through that receptor. No record in this collection tests a benzodiazepine on human T cells.
• Whether the extrasynaptic receptors that zinc blocks are the ones a therapeutic neurosteroid acts through in people.Zinc selectively abolished neurosteroid potentiation of extrasynaptic tonic current in mouse hippocampus while sparing synaptic phasic current, and an intravenous neurosteroid reduces depression scores in randomised trials. No record here connects the two: the clinical trial does not identify a receptor population, and the mouse work does not measure mood.

Chapters are assembled from supplied drafts and curated literature summaries. Statements remain unverified against the primary studies, and the ledger is not medical advice.