White_1986_Gen.Pharmacol_17_497

The importance of the endothelium for isoproterenol- and salbutamol-induced relaxation of canine coronary artery was examined. The relaxation effect of isoproterenol and salbutamol was significantly enhanced (P less than 0.05) upon removal of the coronary artery endothelium. In contrast, the relaxation effect of acetylcholine was completely abolished. These results indicate that canine coronary endothelium modulates beta-adrenoceptor-mediated relaxation, and that the role of the endothelium in agonist-induced relaxation of vascular smooth muscle appears to be heterogeneous.