Coronary and internal mammary and radial arteries: molecular mechanisms & dependencies

How nutrients influence it

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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

Sildenafil from 10 nanomolar to 30 micromolar caused concentration-dependent relaxation in internal mammary arteries, radial arteries and forearm veins with a modest relaxant effect in coronary arteries, amplified the relaxation induced by sodium nitroprusside in all four vessels, and relaxation was unaffected by the nitric oxide synthase inhibitor NG-monomethyl-L-arginine at 100 micromolar, the drug being eight to ten times more potent than zaprinast.
Sildenafil → Coronary and internal mammary and radial arteries source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/sildenafil-research/11081893.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7425aaede1777ba3689df435384bb535635a8181487b1937154eb635a01c9dbb", "start_char": 0, "end_char": 1602, "text_sha256": "7425aaede1777ba3689df435384bb535635a8181487b1937154eb635a01c9dbb"}
experimental_model
Organ bath studies on coronary, internal mammary and radial arteries and forearm veins from sixteen multiorgan donors
exposure
Sildenafil from 10 nanomolar to 30 micromolar on precontracted vessels, with nitric oxide synthase inhibition
limitations
Extends the same finding to conduit arteries used in bypass surgery. Again the upper concentrations are far above therapeutic and the relaxation in coronary artery was modest.
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
The same direct relaxation appears in the arteries used for bypass grafts, and it too survives blocking nitric oxide synthesis.
primary_references
[sil-p11081893] Relaxation induced by cGMP phosphodiesterase inhibitors sildenafil and zaprinast in human vessels. (2000). https://pubmed.ncbi.nlm.nih.gov/11081893/ DOI: 10.1016/s0003-4975(00)01914-7
tissue_or_cell_type
Arterial and venous conduits
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 366–377
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Organ bath studies on coronary, internal mammary and radial arteries and forearm veins from sixteen multiorgan donors · source_derived_draft · unverified_draft
### sil-conduit-arteries-relax-too Sildenafil from 10 nanomolar to 30 micromolar caused concentration-dependent relaxation in internal mammary arteries, radial arteries and forearm veins with a modest relaxant effect in coronary arteries, amplified the relaxation induced by sodium nitroprusside in all four vessels, and relaxation was unaffected by the nitric oxide synthase inhibitor NG-monomethyl-L-arginine at 100 micromolar, the drug being eight to ten times more potent than zaprinast. 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: The same direct relaxation appears in the arteries used for bypass grafts, and it too survives blocking nitric oxide synthesis. organism: Human tissue_or_cell_type: Arterial and venous conduits experimental_model: Organ bath studies on coronary, internal mammary and radial arteries and forearm veins from sixteen multiorgan donors limitations: Extends the same finding to conduit arteries used in bypass surgery. Again the upper concentrations are far above therapeutic and the relaxation in coronary artery was modest. exposure: Sildenafil from 10 nanomolar to 30 micromolar on precontracted vessels, with nitric oxide synthase inhibition evidence_span: {"source_cache": "artifacts/sildenafil-research/11081893.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7425aaede1777ba3689df435384bb535635a8181487b1937154eb635a01c9dbb", "start_char": 0, "end_char": 1602, "text_sha256": "7425aaede1777ba3689df435384bb535635a8181487b1937154eb635a01c9dbb"} [sil-p11081893] Relaxation induced by cGMP phosphodiesterase inhibitors sildenafil and zaprinast in human vessels. (2000). https://pubmed.ncbi.nlm.nih.gov/11081893/ DOI: 10.1016/s0003-4975(00)01914-7
Complete structured claim and evidence

Where it participates (unsigned role)

In haemodynamic studies sildenafil produced small decreases in systemic and pulmonary blood pressure but caused no adverse cardiovascular effects in specific populations of men with coronary heart disease, and it caused no significant changes in coronary blood flow but had a positive effect on coronary flow reserve in men with severe coronary artery disease, suggesting that PDE5 may play an important role in the regulation of coronary blood flow in the healthy and diseased heart, while in retrospective analyses of extensive clinical trials treatment was not associated with any increase in cardiac risk in patients not receiving organic nitrates or nitrate donor drugs.
Sildenafil → Coronary blood flow and coronary flow reserve source_derived_draftungraded
Experimental context and source evidence
evidence_span
{"source_cache": "artifacts/sildenafil-research/11351772.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "73a1ab2fa66fb9a6155ab7ccae7f405568ffdee07d4a09d61dc106e00c442711", "start_char": 0, "end_char": 1020, "text_sha256": "73a1ab2fa66fb9a6155ab7ccae7f405568ffdee07d4a09d61dc106e00c442711"}
experimental_model
Review of the coronary vascular profile assembled from haemodynamic studies and retrospective analysis of the clinical trial programme
exposure
Sildenafil at therapeutic doses in men with coronary heart disease not taking nitrates
limitations
A review rather than a new study, and the cardiac risk analyses are retrospective. It measures coronary flow in the intact circulation, where the organ bath records cannot.
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 the living coronary circulation it did not change resting flow, though it improved the reserve the vessels could call on.
primary_references
[sil-p11351772] Phosphodiesterase 5 inhibition: effects on the coronary vasculature. (2001). https://pubmed.ncbi.nlm.nih.gov/11351772/ DOI: 10.1111/j.1742-1241.2001.tb11011.x
tissue_or_cell_type
Coronary circulation
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 379–390
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Review of the coronary vascular profile assembled from haemodynamic studies and retrospective analysis of the clinical trial programme · source_derived_draft · unverified_draft
### sil-no-change-in-coronary-flow In haemodynamic studies sildenafil produced small decreases in systemic and pulmonary blood pressure but caused no adverse cardiovascular effects in specific populations of men with coronary heart disease, and it caused no significant changes in coronary blood flow but had a positive effect on coronary flow reserve in men with severe coronary artery disease, suggesting that PDE5 may play an important role in the regulation of coronary blood flow in the healthy and diseased heart, while in retrospective analyses of extensive clinical trials treatment was not associated with any increase in cardiac risk in patients not receiving organic nitrates or nitrate donor drugs. 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 the living coronary circulation it did not change resting flow, though it improved the reserve the vessels could call on. organism: Human tissue_or_cell_type: Coronary circulation experimental_model: Review of the coronary vascular profile assembled from haemodynamic studies and retrospective analysis of the clinical trial programme limitations: A review rather than a new study, and the cardiac risk analyses are retrospective. It measures coronary flow in the intact circulation, where the organ bath records cannot. exposure: Sildenafil at therapeutic doses in men with coronary heart disease not taking nitrates evidence_span: {"source_cache": "artifacts/sildenafil-research/11351772.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "73a1ab2fa66fb9a6155ab7ccae7f405568ffdee07d4a09d61dc106e00c442711", "start_char": 0, "end_char": 1020, "text_sha256": "73a1ab2fa66fb9a6155ab7ccae7f405568ffdee07d4a09d61dc106e00c442711"} [sil-p11351772] Phosphodiesterase 5 inhibition: effects on the coronary vasculature. (2001). https://pubmed.ncbi.nlm.nih.gov/11351772/ DOI: 10.1111/j.1742-1241.2001.tb11011.x
Complete structured claim and evidence

The events it takes part in

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Situations it appears in

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In the sources

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Open hypotheses

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

Coronary and internal mammary and radial arteries