α-Adrenergic coronary vasoconstriction and myocardial ischemia in humans

Abstract

The use of quantitative coronary angiography, combined with Doppler and PET, has recently been directed at the study of α-adrenergic coronary vasomotion in humans. Confirming prior animal experiments, there is no evidence of α-adrenergic coronary constrictor tone at rest. Again confirming prior experiments, responses to α-adrenoceptor activation are augmented in the presence of coronary endothelial dysfunction and atherosclerosis, involving both α1- and α2-adrenoceptors in epicardial conduit arteries and microvessels. Such augmented α-adrenergic coronary constriction is observed during exercise and coronary interventions, and it is powerful enough to induce myocardial ischemia and limit myocardial function. Recent studies indicate a genetic determination of α2-adrenergic coronary constriction.