Kwan Y W, Wadsworth R M, Kane K A
Department of Physiology and Pharmacology, University of Strathclyde, Glasgow, Scotland, U.K.
Eur J Pharmacol. 1989 Sep 1;168(1):31-8. doi: 10.1016/0014-2999(89)90629-8.
The effects of simulated myocardial ischaemia on tone and on the responsiveness to contractile and relaxant agents were examined on sheep circumflex coronary artery rings. Introduction of ischaemia caused a transient relaxation followed by sustained contraction which was inhibited by adenosine or by the removal of the endothelium. Under ischaemic conditions, the contractile effects of 5-hydroxytryptamine and acetylcholine were markedly depressed while those of potassium and U46619 (a stable thromboxane analogue) were not modified. In contrast, the vasodilating effects of adenosine, noradrenaline and iloprost (a prostacyclin mimetic) were significantly potentiated. Addition of adenosine to the ischaemic Krebs solution abolished the contractile effects of 5-hydroxytryptamine and U46619 but did not modify the vasorelaxant effects of noradrenaline and iloprost. These results indicate that the ischaemic-induced contraction is endothelium-dependent and the responsiveness of the coronary artery to both constrictors and vasodilators changed under conditions of simulated myocardial ischaemia.
在绵羊冠状动脉环上研究了模拟心肌缺血对张力以及对收缩剂和舒张剂反应性的影响。引入缺血导致短暂舒张，随后是持续收缩，腺苷或去除内皮可抑制这种收缩。在缺血条件下，5-羟色胺和乙酰胆碱的收缩作用明显降低，而钾和U46619（一种稳定的血栓素类似物）的收缩作用未改变。相反，腺苷、去甲肾上腺素和伊洛前列素（一种前列环素类似物）的舒张作用显著增强。向缺血的 Krebs 溶液中添加腺苷可消除 5-羟色胺和 U46619 的收缩作用，但不改变去甲肾上腺素和伊洛前列素的血管舒张作用。这些结果表明，缺血诱导的收缩是内皮依赖性的，并且在模拟心肌缺血条件下冠状动脉对收缩剂和舒张剂的反应性发生了改变。
