Endothelium-derived relaxing factor in human coronary artery.

Over the last few years it has become apparent that endothelial cells release many vasoactive substances, including prostacyclin, endothelium-derived relaxing factor (EDRF), endothelium-derived contracting factor(s), and endothelium-derived hyperpolarizing factor. The picture that is rapidly emerging from research in this field is that abnormalities in the production and release of these substances may occur and contribute to many pathophysiologic states. For example, an impaired release of EDRF, the endogenous prototype of the nitrovasodilator drugs and a powerful vasodilator, appears to be involved in abnormal vasomotor function in diseases, such as atherosclerosis and hypertension. This view is supported by recent pharmacological experiments with isolated human coronary arteries freshly obtained from patients at heart transplantation, and clinical studies using quantitative coronary angiography. However, even in atherosclerotic arteries, EDRF-mediated vasodilation may contribute considerably to the actual vascular tone, since the release of EDRF upon appropriate stimulation in patients with moderate coronary artery disease appears to result in a vasodilation which is similar to that induced by an intracoronary infusion of nitroglycerin.