The Psychedelic Psilocin Suppresses Activity of Central Amygdala Corticotropin-Releasing Factor Receptor 1 Neurons and Decreases Ethanol Drinking in Female Mice.

Alcohol use disorder (AUD) is a highly prevalent disorder with limited therapeutic options. The central amygdala (CeA) is a critical brain region as dysregulation within the CeA and the corticotropin-releasing factor (CRF) system are associated with AUD pathology. CeA CRF1 receptors regulate alcohol drinking and have served as a therapeutic target in alcohol treatment. One emerging potential therapeutic for AUD is psilocybin. Psilocybin has been shown to decrease drinking in some clinical studies; however, the effects are variable and the underlying mechanisms are poorly understood. Psilocybin engages many brain regions, including the CeA, and may produce therapeutic effects on drinking through interactions with CeA CRF1 neurons. The current study explores the effects of psilocin, the active metabolite of psilocybin, on voluntary ethanol drinking and CeA CRF1 activity to understand potential mechanisms underlying the therapeutic effects of psilocin. Psilocin acutely decreased ethanol consumption in mice exposed to two different models of chronic ethanol exposure without producing changes in locomotor behavior. Psilocin increased CeA activation and decreased relative CRF1 activation in CeA subregions from ethanol-naive female CRF1:GFP mice. These results were also observed in chronic ethanol-exposed mice at 24 and 72 h withdrawal timepoints. Psilocin increased corticosterone at 24 h withdrawal but not at 72 h withdrawal. Collectively, these results demonstrate that psilocin engages CeA circuitry and decreases relative CRF1 activation, in parallel with acute reductions in drinking. These results contribute to our understanding of the mechanisms underlying the actions of psilocin and inform the interpretation of therapeutic effects in clinical studies.