The mechanism of ergometrine-induced coronary arterial spasm: in vitro studies on canine arteries.

摘要: The mechanism by which ergometrine provokes coronary vasospasm was investigated in vitro. Changes tension were monitored isometrically on spiral strips of freshly obtained (ventricular and circumflex branches) basilar arteries from dogs. Cumulative concentration-response curves established for noradrenaline, adrenaline, 5-hydroxytryptamine (5-HT), ergometrine. catecholamines either contracted or relaxed the vascular smooth muscle stimulating alpha- beta-adrenoceptors, respectively, whereas both 5-HT consistently induced contraction arteries. In order to antagonize ergometrine-induced arteries, appromimately 60-fold greater concentrations phentolamine required compared those necessary antagonism noradrenaline. curve noradrenaline unchanged ergometrine, indicating that two compounds combine with different receptors. use antagonists phentolamine, indoramine, pimozide, pizotifen, methysergide provided evidence induce same type receptor, which, however, seems be receptor present It is suggested Prinzmetal's variant form angina, can provoke increasing tone via stimulation receptors, thus reinforcing sympathetic tone.