Selectively counteracting cerebellar adaptations to chronic alcohol exposure reduces acute alcohol withdrawal severity in C57BL6/N mice

Abstract

A critical component of Alcohol Use Disorder (AUD) is alcohol (EtOH) withdrawal and consequent aversive withdrawal symptoms that generate negative reinforcement for renewed EtOH consumption to alleviate such symptoms. Here, we simulated human binge EtOH consumption and subsequent acute withdrawal by exposing male and female C57BL6/N mice to EtOH vapor for varying durations (24-72 h). During acute withdrawal, starting 4 h after removal from EtOH vapor, we used patch-clamp recording in cerebellar slices, combined with behavioral analysis of aversive somatic/motor (performance on the accelerating rotorod) and affective/emotional (ultrasonic vocalizations and blood corticosterone) withdrawal symptoms. We found that cerebellar granule cells (GCs) exhibit a homeostatic downregulation of sIPSC frequency that parallels development of motor discoordination and negative emotional affect, all starting at ∼48-72 h of EtOH vapor exposure. Fitting with the negative reinforcement component of the AUD cycle, re-exposure to EtOH during withdrawal reduced somatic and affective withdrawal symptoms. Importantly, selective chemogenetic inhibition of GCs during withdrawal improved motor coordination, likely via actions at the GC axon terminals, and selective pharmacological inhibition of GCs via enhancement of the tonic GABAAR current, using PZ-II-019 (Compound 6), significantly improved negative emotional affect. Collectively, these results indicate that cerebellar homeostatic adaptations mediate aspects of both somatic and affective aversive EtOH withdrawal symptoms, and that restoration of cerebellar adaptations can effectively treat such symptoms. Moreover, they highlight the cerebellum as a promising selective target for treating aversive EtOH withdrawal symptoms, a critical component of the AUD cycle.