Salivation mediated by central M-2 muscarinic receptors in the cat

In these experiments the effect on the cat's salivation of the choline ester, carbachol, the anticholinesterase, eserine, and the muscarinic ganglionic stimulants, McN-A-343 and AHR-602, injected into the cerebral ventricles was investigated and compared. Carbachol and eserine injected intracerebroventricularly (ICV) produced dose-related salivation. On the other hand, ICV McN-A-343 and AHR-602 evoked inconsistent salivation when injected in large doses. The antimuscarinic drug, atropine, injected into the cerebral ventricles abolished the salivation caused by carbachol and eserine similarly injected. However, salivation induced by ICV carbachol and eserine was not significantly altered by the ganglionic blocking agent, mecamylamine, injected into the cerebral ventricles. It is concluded that the ICV injection of carbachol and eserine evokes salivation in the cat by way of an action on central M-2 muscarinic receptors.