Enhancement of desynchronized sleep signs after pontine microinjection of the muscarinic agonist bethanechol.

Overview

The question of which brainstem neuronal receptors can mediate cholinergic REM sleep induction was investigated by injecting the pure muscarinic agonist bethanechol via glass micropipettes in the pontine tegmentum of cats. The REM sleep enhancement was observed to be equally potent, equally dose-dependent and its appearance equally site-dependent as that previously observed with carbachol, a mixed muscarinic/nicotinic agonist. The results suggest that the pharmacological activation of muscarinic receptors in pontine neurons is sufficient to trigger REM sleep.