The modulatory benzodiazepine-binding site of the GABA-A receptor

Where it participates (unsigned role)

1. 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

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   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

2. 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