Cholinergic regulation of prolonged alcohol withdrawal differs by sex

Acute alcohol withdrawal encompasses somatic withdrawal signs and increased negative affect. In prolonged alcohol withdrawal the somatic withdrawal signs have resolved but the increased negative affect persists. We investigated acute and prolonged alcohol withdrawal after 9 daily injections of 2.5 g/kg alcohol plus 4-methypyrazole, an alcohol dehydrogenase inhibitor, in male and female C57BL/6J mice, and examined whether nicotinic acetylcholine receptor (nAChR) drugs could attenuate withdrawal-induced negative affect. Male mice showed changing somatic withdrawal signs over time and negative affect that persisted at least 21 days into withdrawal. Pre-treatment with mecamylamine, a non-specific nAChR antagonist, or varenicline, a nAChR partial agonist, reduced withdrawal-induced anxiety- and compulsive-like behavior in the marble-burying test during prolonged withdrawal. In contrast, female mice did not exhibit somatic withdrawal signs or anxiety- or compulsive-like behaviors. Instead, female mice showed a deficit in social interaction that was not attenuated by mecamylamine. Alcohol clearance and sedation were not different between sexes, indicating that differences in withdrawal signs and negative affect are not confounded by differences in alcohol metabolism. These findings suggest that cholinergic drugs may be a promising therapeutic for withdrawal-induced negative affect in male, but not female, mice.