Role of autonomic nerves and endothelium in coronary vasospasm

Coronary vasospasm may result from exaggerated contraction of the smooth muscle composing the arterial wall. An imbalance of the autonomic or humoral control of the smooth muscle might serve to initiate a pathological arterial contraction. Abnormal adrenergic or cholinergic nervous function might explain vasospasm of otherwise normal coronaries. Intimal damage due to disease leaves the smooth muscle deficient in the protective metabolic and vasodilator properties of the endothelium. The vasoactive substances released by the platelets aggregating at such a site could cause vasospasm by acting directly on the smooth muscle or by inhibiting the function of dilator nerves.