Catecholaminergic and muscarinergic receptors in chronic experimental uremia

In chronic uremic rats the density of alpha 1- and alpha 2-adrenoceptors in the cerebral cortex was significantly increased while beta-adrenoceptors and muscarinergic receptors in heart and brain as well as cardiac alpha 1-adrenoceptors were unchanged. Only the binding of the alpha 2-selective ligand 3H-clonidine was inhibited by uremic serum. In isolated left ventricular muscle strips dose-effect curves of (-)-noradrenaline and (+/-)-dobutamine were not significantly different in uremic and control animals whereas the negative inotropic action of the muscarinergic agonist carbachol was attenuated.