Central muscarinic activities of an M1-selective agonist: preferential effect on reversal of amnesia.

Effects of FKS-508 (AF102B; cis-2-methylspiro (1,3-oxathiolane-5,3')-quinuclidine), a novel M1-selective agonist, on central muscarinic responses in mice were examined in comparison with oxotremorine. FKS-508 was slightly less potent (6 times) in reversal of scopolamine-induced amnesia (passive avoidance failure), but far less potent (260 and 55 times) in producing hypothermia and tremor than oxotremorine. These results show that the selective M1 agonist FKS-508 differentiates highly between the central muscarinic effects.