Coronary effects of endothelin-1 during acute hypertension in anaesthetized goats.
The coronary effects of endothelin-1 (ET-1) during acute hypertension were examined in anesthetized goats, where the left circumflex coronary artery flow was electromagnetically measured and hypertension was induced by constriction of the thoracic aorta. In six non-treated goats, aortic constriction increased arterial pressure (mean arterial pressure=128+/-5 mmHg) and coronary flow (by 34%) without changing coronary vascular conductance. In this case, ET-1 (0.01-0.3 nmol) when injected intracoronarily, decreased coronary vascular conductance, which was similar in hypertension and in normotension. In eight N(G)-nitro-L-arginine methyl ester-treated goats, aortic constriction increased arterial pressure (mean arterial pressure=131+/-5 mmHg) and coronary flow (by 26%) and decreased coronary vascular conductance (by 17%). In this case, ET-1 (0.01-0.3 nmol) also decreased coronary vascular conductance, which was similar in N(G)-nitro-L-arginine methyl ester-treated hypertension that observed in normotension. Therefore, acute hypertension attenuates the coronary vasoconstriction caused by ET-1, and this attenuation might be related to mechanisms other than changes in NO release.
Fernández
Nuria
N
Departamento de Fisiología, Facultad de Medicina, Universidad Autónma, Arzobispo Morcillo 2, 28029 Madrid, Spain.
Angeles Martínez
María
M
García-Villalón
Angel Luis
AL
Monge
Luis
L
Diéguez
Godofredo
G
D000208:Acute Disease; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D019332:Endothelin-1 / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D005260:Female; D006041:Goats; D006973:Hypertension / Q000503:physiopathology*; D019331:NG-Nitroarginine Methyl Ester / Q000627:therapeutic use; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D014655:Vascular Resistance / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D019332:Endothelin-1; D004791:Enzyme Inhibitors; D014662:Vasoconstrictor Agents; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester