alpha-Adrenergic coronary vasoconstriction and myocardial ischemia in humans

The use of quantitative coronary angiography, combined with Doppler and PET , has recently been directed at the study of alpha-adrenergic coronary vaso motion in humans. Confirming prior animal experiments, there is no evidence of alpha-adrenergic coronary constrictor tone at rest. Again confirming pr ior experiments, responses to alpha-adrenoceptor activation are augmented i n the presence of coronary endothelial dysfunction and atherosclerosis, inv olving both alpha(1)- and alpha(2)-adrenoceptors in epicardial conduit arte ries and microvessels. Such augmented alpha-adrenergic corollary constricti on is observed during exercise and coronary interventions, and it is powerf ul enough to induce myocardial ischemia and limit myocardial function. Rece nt studies indicate a genetic determination of alpha(2)-adrenergic coronary constriction.