Component

Human corpus cavernosum trabecular smooth muscle

Human corpus cavernosum trabecular smooth muscle. Species, exposure and limitations are retained in each linked claim.

3 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What acts on it

  1. Both cyclic GMP and cyclic AMP specific phosphodiesterases were identified in human corpora cavernosa in vitro, the main phosphodiesterase activity in this tissue being due to PDE5 with PDE2 and PDE3 also identified, and sildenafil is a selective inhibitor of PDE5 with a mean half-maximal inhibitory concentration of 0.0039 micromolar.

    Phosphodiesterase 5 family → Human corpus cavernosum trabecular smooth muscle source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/sildenafil-research/8858389.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "173f69debd8427b8a1c001e543e4356f2d3b90c730ca3217073a25c4bc61905a", "start_char": 0, "end_char": 1288, "text_sha256": "173f69debd8427b8a1c001e543e4356f2d3b90c730ca3217073a25c4bc61905a"}
    experimental_model
    Phosphodiesterase isozyme characterisation in human corpora cavernosa with volunteer pharmacokinetics and a small clinical study
    exposure
    Sildenafil assayed against phosphodiesterase isozymes prepared from human tissue
    limitations
    The first report of the compound. The clinical arm is twelve patients without an established organic cause, so it establishes the target rather than the treatment effect.
    nutrient_topic
    Sildenafil research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from its N-desmethyl metabolite and its target enzyme from the homologous retinal PDE6. · Sildenafil
    organism
    Human
    plain_language
    One of the several enzymes in this tissue carries most of the activity, and the drug was built against that one.
    primary_references
    [sil-p8858389] Sildenafil: an orally active type 5 cyclic GMP-specific phosphodiesterase inhibitor for the treatment of penile erectile dysfunction. (1996). https://pubmed.ncbi.nlm.nih.gov/8858389/
    tissue_or_cell_type
    Corpus cavernosum

    Sildenafil: the enzyme it occupies instead of the substrate, why it cannot start a signal it can only preserve, the organic nitrate interaction that follows from that, the homologous retinal enzyme ten-fold away, and the pulmonary circulation where the same mechanism became a second indication (2026-09-22) · lines 119–130

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Phosphodiesterase isozyme characterisation in human corpora cavernosa with volunteer pharmacokinetics and a small clinical study · source_derived_draft · unverified_draft

    ### sil-pde5-is-the-main-isozyme Both cyclic GMP and cyclic AMP specific phosphodiesterases were identified in human corpora cavernosa in vitro, the main phosphodiesterase activity in this tissue being due to PDE5 with PDE2 and PDE3 also identified, and sildenafil is a selective inhibitor of PDE5 with a mean half-maximal inhibitory concentration of 0.0039 micromolar. Condition category: normal nutrient_topic: Sildenafil research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from its N-desmethyl metabolite and its target enzyme from the homologous retinal PDE6. plain_language: One of the several enzymes in this tissue carries most of the activity, and the drug was built against that one. organism: Human tissue_or_cell_type: Corpus cavernosum experimental_model: Phosphodiesterase isozyme characterisation in human corpora cavernosa with volunteer pharmacokinetics and a small clinical study limitations: The first report of the compound. The clinical arm is twelve patients without an established organic cause, so it establishes the target rather than the treatment effect. exposure: Sildenafil assayed against phosphodiesterase isozymes prepared from human tissue evidence_span: {"source_cache": "artifacts/sildenafil-research/8858389.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "173f69debd8427b8a1c001e543e4356f2d3b90c730ca3217073a25c4bc61905a", "start_char": 0, "end_char": 1288, "text_sha256": "173f69debd8427b8a1c001e543e4356f2d3b90c730ca3217073a25c4bc61905a"} [sil-p8858389] Sildenafil: an orally active type 5 cyclic GMP-specific phosphodiesterase inhibitor for the treatment of penile erectile dysfunction. (1996). https://pubmed.ncbi.nlm.nih.gov/8858389/
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Sildenafil at 0.001 to 1 micromolar enhanced the electrical-field-stimulation-induced, nitric-oxide-dependent relaxation of human corpus cavernosum in a concentration-dependent manner to a maximum of three times the pretreatment level at 1 micromolar, supporting the proposal that the drug acts by potentiating the nitric-oxide-stimulated cyclic GMP signal mediating relaxation of cavernosal smooth muscle during sexual stimulation.

    Sildenafil → Relaxation of vascular and trabecular smooth muscle source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/sildenafil-research/9598563.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "860e09237bbae4ec5bb65a640186902908ccb9c6ec502b504a1ecddbb33810a2", "start_char": 0, "end_char": 1755, "text_sha256": "860e09237bbae4ec5bb65a640186902908ccb9c6ec502b504a1ecddbb33810a2"}
    experimental_model
    Isolated human corpus cavernosum strips with electrical field stimulation, and phosphodiesterase assays across families 1 to 6
    exposure
    Sildenafil against PDE1 to PDE5 prepared from human tissues and PDE6 from bovine retina, with zaprinast as comparator
    limitations
    Measures the full selectivity series in one laboratory using the same method, which is what makes the ratios comparable. The PDE6 preparation is bovine retina rather than human.
    nutrient_topic
    Sildenafil research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from its N-desmethyl metabolite and its target enzyme from the homologous retinal PDE6. · Sildenafil
    organism
    Human and bovine enzyme
    plain_language
    It triples a relaxation the nerves were already producing; it does not produce one of its own.
    primary_references
    [sil-p9598563] Effects of sildenafil on the relaxation of human corpus cavernosum tissue in vitro and on the activities of cyclic nucleotide phosphodiesterase isozymes. (1998). https://pubmed.ncbi.nlm.nih.gov/9598563/ DOI: 10.1016/s0022-5347(01)63299-3
    tissue_or_cell_type
    Corpus cavernosum and bovine retina

    Sildenafil: the enzyme it occupies instead of the substrate, why it cannot start a signal it can only preserve, the organic nitrate interaction that follows from that, the homologous retinal enzyme ten-fold away, and the pulmonary circulation where the same mechanism became a second indication (2026-09-22) · lines 145–156

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Isolated human corpus cavernosum strips with electrical field stimulation, and phosphodiesterase assays across families 1 to 6 · source_derived_draft · unverified_draft

    ### sil-amplifies-nitrergic-relaxation Sildenafil at 0.001 to 1 micromolar enhanced the electrical-field-stimulation-induced, nitric-oxide-dependent relaxation of human corpus cavernosum in a concentration-dependent manner to a maximum of three times the pretreatment level at 1 micromolar, supporting the proposal that the drug acts by potentiating the nitric-oxide-stimulated cyclic GMP signal mediating relaxation of cavernosal smooth muscle during sexual stimulation. Condition category: normal nutrient_topic: Sildenafil research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from its N-desmethyl metabolite and its target enzyme from the homologous retinal PDE6. plain_language: It triples a relaxation the nerves were already producing; it does not produce one of its own. organism: Human and bovine enzyme tissue_or_cell_type: Corpus cavernosum and bovine retina experimental_model: Isolated human corpus cavernosum strips with electrical field stimulation, and phosphodiesterase assays across families 1 to 6 limitations: Measures the full selectivity series in one laboratory using the same method, which is what makes the ratios comparable. The PDE6 preparation is bovine retina rather than human. exposure: Sildenafil against PDE1 to PDE5 prepared from human tissues and PDE6 from bovine retina, with zaprinast as comparator evidence_span: {"source_cache": "artifacts/sildenafil-research/9598563.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "860e09237bbae4ec5bb65a640186902908ccb9c6ec502b504a1ecddbb33810a2", "start_char": 0, "end_char": 1755, "text_sha256": "860e09237bbae4ec5bb65a640186902908ccb9c6ec502b504a1ecddbb33810a2"} [sil-p9598563] Effects of sildenafil on the relaxation of human corpus cavernosum tissue in vitro and on the activities of cyclic nucleotide phosphodiesterase isozymes. (1998). https://pubmed.ncbi.nlm.nih.gov/9598563/ DOI: 10.1016/s0022-5347(01)63299-3
    Complete structured claim and evidence

  2. In the concentration range 0.01 to 1 micromolar there was only a minor effect of sildenafil on cyclic GMP levels in isolated human cavernous and cardiac tissues, whereas sildenafil significantly increased cyclic AMP in both at physiologic and supraphysiologic concentrations, more pronounced in cavernous than cardiac tissue, and in the range 0.1 to 1.0 micromolar the effect on cyclic AMP in cardiac samples was almost equivalent to that of milrinone, which the authors offer as a potential mechanism for reported cardiovascular effects and as evidence of cross-talk between the two signalling pathways.

    Sildenafil → Cyclic adenosine monophosphate source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/sildenafil-research/10654914.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "95ba66c3ea65d0610adf58e7ab0bca314da8353ecac3f86272c780678929d292", "start_char": 0, "end_char": 1867, "text_sha256": "95ba66c3ea65d0610adf58e7ab0bca314da8353ecac3f86272c780678929d292"}
    experimental_model
    Radioimmunoassay of cyclic nucleotide accumulation in isolated human corpus cavernosum and cardiac muscle
    exposure
    Sildenafil from 0.01 to 1 micromolar against sodium nitroprusside, forskolin and milrinone as reference compounds
    limitations
    Measures both cyclic nucleotides in human tissue with reference compounds for each pathway, and reports an effect on the nucleotide the drug is not supposed to touch. It is an isolated tissue study without added nitric oxide drive.
    nutrient_topic
    Sildenafil research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from its N-desmethyl metabolite and its target enzyme from the homologous retinal PDE6. · Sildenafil
    organism
    Human
    plain_language
    In this tissue the drug barely moved the messenger it targets and raised the other one instead.
    primary_references
    [sil-p10654914] Effects of sildenafil on cAMP and cGMP levels in isolated human cavernous and cardiac tissue. (2000). https://pubmed.ncbi.nlm.nih.gov/10654914/ DOI: 10.1016/s0090-4295(99)00371-4
    tissue_or_cell_type
    Corpus cavernosum and cardiac muscle

    Sildenafil: the enzyme it occupies instead of the substrate, why it cannot start a signal it can only preserve, the organic nitrate interaction that follows from that, the homologous retinal enzyme ten-fold away, and the pulmonary circulation where the same mechanism became a second indication (2026-09-22) · lines 392–403

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Radioimmunoassay of cyclic nucleotide accumulation in isolated human corpus cavernosum and cardiac muscle · source_derived_draft · unverified_draft

    ### sil-cyclic-amp-rose-instead In the concentration range 0.01 to 1 micromolar there was only a minor effect of sildenafil on cyclic GMP levels in isolated human cavernous and cardiac tissues, whereas sildenafil significantly increased cyclic AMP in both at physiologic and supraphysiologic concentrations, more pronounced in cavernous than cardiac tissue, and in the range 0.1 to 1.0 micromolar the effect on cyclic AMP in cardiac samples was almost equivalent to that of milrinone, which the authors offer as a potential mechanism for reported cardiovascular effects and as evidence of cross-talk between the two signalling pathways. Condition category: normal nutrient_topic: Sildenafil research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from its N-desmethyl metabolite and its target enzyme from the homologous retinal PDE6. plain_language: In this tissue the drug barely moved the messenger it targets and raised the other one instead. organism: Human tissue_or_cell_type: Corpus cavernosum and cardiac muscle experimental_model: Radioimmunoassay of cyclic nucleotide accumulation in isolated human corpus cavernosum and cardiac muscle limitations: Measures both cyclic nucleotides in human tissue with reference compounds for each pathway, and reports an effect on the nucleotide the drug is not supposed to touch. It is an isolated tissue study without added nitric oxide drive. exposure: Sildenafil from 0.01 to 1 micromolar against sodium nitroprusside, forskolin and milrinone as reference compounds evidence_span: {"source_cache": "artifacts/sildenafil-research/10654914.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "95ba66c3ea65d0610adf58e7ab0bca314da8353ecac3f86272c780678929d292", "start_char": 0, "end_char": 1867, "text_sha256": "95ba66c3ea65d0610adf58e7ab0bca314da8353ecac3f86272c780678929d292"} [sil-p10654914] Effects of sildenafil on cAMP and cGMP levels in isolated human cavernous and cardiac tissue. (2000). https://pubmed.ncbi.nlm.nih.gov/10654914/ DOI: 10.1016/s0090-4295(99)00371-4
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

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