Institut für Pathophysiologie, Universitätsklinikum Essen, Hufelandstr. 55, 45122 Essen, Germany.
J Mol Cell Cardiol. 2011 Jul;51(1):16-23. doi: 10.1016/j.yjmcc.2011.03.007. Epub 2011 Mar 30.
Activation of coronary vascular α-adrenoceptors results in vasoconstriction which competes with metabolic vasodilation during sympathetic activation. Epicardial conduit vessel constriction is largely mediated by α(1)-adrenoceptors; the constriction of the resistive microcirculation largely by α(2)-adrenoceptors, but also by α(1)-adrenoceptors. There is no firm evidence that α-adrenergic coronary vasoconstriction exerts a beneficial effect on transmural blood flow distribution. In fact, α-blockade in anesthetized and conscious dogs improves blood flow to all transmural layers, during normoperfusion and hypoperfusion. Also, in patients with coronary artery disease, blockade of α(1)- and α(2)-adrenoceptors improves coronary blood flow, myocardial function and metabolism.
冠状动脉血管α-肾上腺素受体的激活导致血管收缩，这在交感神经激活时与代谢性血管扩张相竞争。心外膜导管血管的收缩主要由α(1)-肾上腺素受体介导；阻力微循环的收缩主要由α(2)-肾上腺素受体介导，但也由α(1)-肾上腺素受体介导。没有确凿的证据表明α-肾上腺素能冠状动脉收缩对跨壁血流分布有有益的影响。事实上，在麻醉和清醒的狗中，α-阻断剂在正常灌注和低灌注期间改善所有跨壁层的血流。此外，在患有冠状动脉疾病的患者中，阻断α(1)-和α(2)-肾上腺素受体可改善冠状动脉血流、心肌功能和代谢。
