[The role of the endothelium in the beta-adrenergic regulation of vascular tonus].

Abstract The effects of beta-adrenoreceptors agonists and antagonists on vascular tone were studied. Activation of beta-adrenoreceptors led to vasomotor reaction irrespective of the endothelium, through a direct effect on the smooth muscle elements of the vascular wall. The dilating effect of propranolol is determined by its interaction with endothelial cells which leads to the PGI2 and, perhaps, EDRF release.