Assessing the utility of the neurosteroid zuranolone to modify alcohol-related behaviours.

Alcohol use is a leading risk factor for premature mortality, yet effective pharmacotherapies remain limited. Neurosteroids, such as allopregnanolone, modulate γ-aminobutyric acid type A (GABAA) receptors and influence alcohol-related behaviours. Zuranolone, an orally bioavailable synthetic analogue of allopregnanolone recently approved for postpartum depression, represents a potential candidate for therapeutic repurposing in alcohol use disorder (AUD). Here, we assessed the effects of acute and daily zuranolone on alcohol-related behaviours in a preclinical binge drinking model, comparing outcomes across sexes and contrasted to the effects of allopregnanolone. Allopregnanolone produced dose-related locomotor responses, characterised by mid dose transient hyperlocomotion and high dose sedation; the mid dose also reduced alcohol intake in both sexes. In contrast, zuranolone produced sex- and dosing schedule-related effects on alcohol consumption: acute high dose administration transiently reduced intake in males in the Latin square design, whereas mid dose administration increased intake under dose escalation in both sexes, particularly in males; however, total intake was unchanged across dosing schedules. Daily zuranolone transiently reduced alcohol intake in males during the first week only. In locomotor assays, acute high dose zuranolone induced sustained hyperactivity in males that was attenuated in females, supporting sex-related differences in sensitivity. Despite its structural similarity to allopregnanolone, zuranolone produced unique behavioural responses, suggesting their pharmacological profiles may differ. Overall, our data do not show robust reductions in alcohol intake following zuranolone administration across dosing schedules in either sex in preclinical models of binge drinking. Future studies are required to explore its potential relevance in comorbid AUD and affective disorders.