Effects of a M1 muscarinic receptor agonist on the central cholinergic system, evaluated by brain microdialysis.

The effects of a novel M1-receptor agonist, AF102B (FKS-508; cis-2-methylspiro(1,3-oxathiolane-5,3')quinuclidine), on the central cholinergic system in vivo were evaluated by determination of acetylcholine (ACh) content in the rat brain after microwave irradiation and by measurement of ACh release with microdialysis perfusion in freely moving rats. Intraperitoneal administration of AF102B resulted in a significant decrease of ACh content in the brain, while AF102B produced an increase of in vivo ACh release. The present results suggest that ACh content in the brain after treatment with muscarinic agents may be related to the changes of ACh release, in which both M1 and M2 muscarinic receptors may be involved.