Conference Proceedings

THE ACETYLCHOLINE PARADOX - A CONSTRICTOR OF HUMAN SMALL CORONARY-ARTERIES EVEN IN THE PRESENCE OF ENDOTHELIUM

JA ANGUS, TM COCKS, GA MCPHERSON, A BROUGHTON

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY | BLACKWELL SCIENCE | Published : 1991

Abstract

1. In animal experiments, acetylcholine is generally a vasodilator acting indirectly by releasing endothelium-derived relaxing factor (EDRF); for example, in dog and rabbit small coronaries mounted in a myograph, acetylcholine caused concentration-dependent relaxation. 2. In human small coronary arteries taken from the atrial appendage, however, acetylcholine caused concentration-dependent contraction with a functionally intact endothelium as shown by the relaxation in response to substance P, another stimulant of EDRF release. 3. We propose that coronary microvessels from various species have variable populations of acetylcholine receptors on the medial smooth muscle that cause contraction ..

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University of Melbourne Researchers