title: Contractile responses of canine coronary collateral vessels.
abstract: This study examines the responses of coronary collateral vessels to various vasoconstrictors and compares them with responses of 3 different divisions of the native coronary arterial trees in dogs. Only high concentrations of phenylephrine induced contractions in collateral vessels and medium coronary arteries, whereas even a high concentration of this agent did not affect small coronary arteries. Lower concentrations of serotonin or ergonovine elicited contractions in collateral vessels, and medium and large coronary arteries, but even a high concentration of these agents did not affect small coronary arteries. Angiotensin II (10(-7) M) elicited prominent contractions in the following order: small vessels, collateral vessels, medium and large coronary arteries. These results indicate that well-developed collateral vessels behave like native medium diameter coronary artery, and that the tonus of collateral vessels is possibly influenced by various vasoactive substances.
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D003097:Collateral Circulation / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects*; D004285:Dogs; D004874:Ergonovine / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D010656:Phenylephrine; D012701:Serotonin; D004874:Ergonovine