Response of Coronary Strips to Acetylcholine, Histamine, 5-Hydroxytryptamine and Adrenaline

In the previous studies (1) on the effects of drugs on coronary circulation we have employed the isolated perfused heart as the test object. It was, however, difficult to interpret whether our data resulted from the effect on the myocardium or on the coronary smooth muscle itself.Hausler and Filippi (2) have made structural analysis of coronary artery strips by studying the mode of action of drugs upon them. Smith (3) demonstrated reactions of isolated, viable coronary arteries to adrenaline, acetylcholine and histamine by angiople thysmographic technique. The response of coronary arteries to drugs described by these workers is exclusively qualitative and dose-response relationship has not been presented. Furchgott and Bhadrakom (4) reported the reactions of aortic strips to drugs and discussed the concentration-activity curves obtained for adrenaline and Furchgott (5) has reviewed the pharmacology of vascular smooth muscle.This study was initiated for the purpose of investigating the actions of drugs on the coronary strips of pig and providing concentration-activity relationship for acetylcholine, histamine, 5-hydroxytryptamine and adrenaline.