The overconsumption of alcohol contributes to a multitude of negative health outcomes, especially in women, who are more susceptible to its effects and more likely to develop alcohol dependence than men with the same early history of alcohol consumption. Binge alcohol drinking is prominent during reproductive years and correlated with high circulating estrogen in women, and rodent studies show that female rodents with intact ovaries consume more alcohol than males. However, the causal role of ovarian E2 in intact animals in alcohol drinking has not been established. Here, we show that intact female mice consume more alcohol and display reduced avoidance behavior when they have elevated levels of circulating E2 during proestrus compared to other estrous cycle stages in individual mice. We found that high ovarian E2 promotes alcohol drinking in females, but not anxiolysis, through rapid nongenomic E2 signaling at ERα in the bed nucleus of the stria terminalis (BNST). Acute administration of intra-BNST E2 in low ovarian E2 mice enhanced binge alcohol intake, while acute systemic inhibition of E2 synthesis and acute blockade of ERα signaling in the BNST reversed the pro-drinking effects of high ovarian E2 status. In contrast, acute E2 manipulations were unable to alter the effects of ovarian E2 status on avoidance behavior, suggesting genomic mechanisms are required for the anxiolytic effects of ovarian E2. We further show that corticotropin-releasing factor (CRF) neurons in the BNST are an important mediator of these effects of rapid E2 signaling, as high E2 rapidly enhanced synaptic excitation of BNST CRF neurons and promoted their pro-alcohol drinking behavioral role. Thus, we uncover a mechanism by which ovarian hormones in intact female mice control alcohol drinking behavior, and we provide the first mechanism by which ovarian E2 control of behavior is mediated by a rapid, nongenomic signaling mechanism.
