To examine coronary reactivity to acetylcholine and endothelin-1 (ET-1) during partial ischaemia and reperfusion, flow in the left circumflex coronary artery was measured electromagnetically, and coronary partial ischaemia was induced by stenosis of this artery in anaesthetized goats. In eight animals not treated with NG-nitro-L-arginine methyl ester (L-NAME), coronary stenosis reduced coronary flow by 45%, mean arterial pressure by 16% and coronary vascular conductance by 34%. During this ischaemia, coronary vasodilatation to acetylcholine (0.003–0.1µg) and sodium nitroprusside (SNP; 1–10µg) was markedly reduced, and coronary vasoconstriction to ET-1 (0.01–0.3nmol) was attenuated. After 30min of reperfusion, coronary flow, mean arterial pressure and coronary vascular conductance remained decreased, and the effects of acetylcholine, SNP and ET-1 were as in control animals. In six goats treated with NG-nitro-L-arginine methyl ester, coronary stenosis reduced coronary flow by 26% and coronary vascular conductance by 24%, but did not affect mean arterial pressure. During this ischaemia, coronary vasodilatation to acetylcholine and SNP was also markedly reduced, but vasoconstriction to ET-1 was unaffected. After 30min of reperfusion, coronary flow and coronary vascular conductance remained decreased and mean arterial pressure was normal; in addition, the effects of acetylcholine were lower, those of SNP were similar and those of ET-1 were higher than in control animals. Therefore partial ischaemia reduces the coronary vasodilator reserve and blunts coronary vasoconstriction to ET-1, and reperfusion does not alter the endothelium-dependent and -independent coronary vasodilatation or vasoconstriction to ET-1.
Coronary responses to endothelin-1 and acetylcholine during partial coronary ischaemia and reperfusion in anaesthetized goats
Maria Angeles MARTÍNEZ, Nuria FERNÁNDEZ, Luis MONGE, Angel Luis GARCÍA-VILLALÓN, Elena SANZ, Godofredo DIÉGUEZ; Coronary responses to endothelin-1 and acetylcholine during partial coronary ischaemia and reperfusion in anaesthetized goats. Clin Sci (Lond) 1 September 2002; 103 (s2002): 194S–197S. doi: https://doi.org/10.1042/CS103S194S
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