NOVEL PERSISTENT ACTIVATION OF MUSCARINIC M-1 RECEPTORS BY XANOMELINE

The muscarinic agonists, xanomeline and carbachol, displayed similar i ntrinsic activities in stimulating neuronal nitric oxide synthase at m uscarinic M-1, receptors in Chinese hamster ovary (CHO) cells, with xa nomeline being more potent. Pre-incubation (I h) with I mu M xanomelin e, followed by extensive washing, resulted in a significantly elevated basal response, which was absent on co-incubation with atropine. This phenomenon was not observed with carbachol. This is the first report of a persistent, receptor-activating effect of a muscarinic agonist. ( C) 1997 Elsevier Science B.V.