Role of the M 1 receptor in regulating circadian rhythms

Abstract

Cholinergic stimuli are potent regulators of the circadian clock in the hypothalamic suprachiasmatic nucleus (SCN). Using a brain slice model, we have found that the SCN clock is subject to muscarinic regulation, a sensitivity expressed only during the night of the clock's 24-h cycle. Pharmacological and signal transduction characteristics are compatible with a response mediated by an M 1 -like receptor. Molecular manipulation of muscarinic receptors will provide important insights as to the receptor subtype(s) regulating circadian rhythms. © 2001 Elsevier Science Inc.