아세칠콜린이 관상동맥 평활근 수축에 미치는 영향

Abstract

Responses to acetylcholine were studied in isolated coronary helical muscle strips of intramural and extr amural vessels. Helical strips of arterial muscle were prepared from pig coronary arteries. All experiments were performed in Tris-buffered Tyrode solution whi ch was aerated with 100% 0, and kept at 35°C. Acetylcholine (l0-8M~ l a-'M) caused dose-dependendy a phasic contraction of both extramural large and intramural small arteries. The contraction was blocked by atropine. Even on K-contracture (40 mM Kη and in Ca"-free Tyrode and also in the La3+ -containing Ca"-free Tyrode solution, acetylcholine (10- ' M) still prod uced a characteristic small phasic contraction The contractions in the Tyrode solution pretreated with verapamil (I mg!1) and in Ca"-free Tyrode solution decreased from peak tensions more rapidly than in those of normal Tyrode solution The results of this experiment suggest that acetylcholine promoted both the mobilization of cellular Ca" and transmembrane Ca"-influx through the stimulation of cholinergic receptor.