Central Amygdala to Lateral Hypothalamus Neuropeptide Y projections as a Target in Sex-Specific Binge-Like Ethanol Consumption in Mice - PROJECT SUMMARY Heavy alcohol use and dependence has become a major public health concern within the United States and across the globe, with limited treatments currently available to those who seek them. Binge intake of alcohol is a significant risk factor to the development of dependence, and this form of intake leads to major health consequences. While men are more commonly diagnosed with alcohol use disorders, the frequency for diagnoses in females has risen in recent years. Furthermore, sex differences in drinking behavior and the underlying neural mechanism remain largely unknown. Our lab, and others, have implicated the role of the central amygdala (CeA) in ethanol consumption in animal models. Corticotrophin releasing factor (CRF) modulates binge-like ethanol drinking in the CeA, and pilot data from our lab shows that silencing CRF+ projections from the CeA to the lateral hypothalamus (LH) leads to a sex-specific reduction of binge-like ethanol drinking in male, but not female, mice. Similarly, CRF1R antagonism and CRF2R agonism in the LH lead to male specific blunting of binge-drinking, suggesting this receptor system’s involvement in modulating binge drinking. CRF, GABA, and Neuropeptide Y (NPY) Y1 receptor (Y1R) are all closely expressed in the CeA, and pilot work from our lab shows Y1R activation in the CeA blunts binge-like ethanol intake, similar to effects seen in males with silenced CRF neurons in the CeA. However, sex-dependent ethanol consumption differences in the NPY system remain uninvestigated. Thus, this proposal focuses on examining potential sex-differences in CeA NPY and Y1R signaling, as well as the role of the Y1R+ CeA LH pathway, in the modulation of binge-like ethanol consumption. Proposed experiments will use a combination of transgenic, chemogenetic, histological, and pharmacological approaches. The well-validated rodent model of binge-like ethanol consumption known as “Drinking in the Dark” (DID) will be used throughout these experiments to identify neural changes. For Aim 1, I will use the designer receptor technology (viral injections of Cre-dependent Y1R-promoter DREADDs in the CeA) and cannulation of the LH in transgenic NPY1R-cre mice to determine if silencing Y1R+ projection neurons from the CeA to the LH will attenuate DID binge-like ethanol intake and associated blood ethanol concentrations (BECs) in male but not female mice. In Aim 2, I will focus on the role of Y1R signaling in the CeA, and whether Y1R agonism can affect binge-like ethanol drinking in a sex-dependent manner, using site-directed pharmacology and an NPY over-expressing viral vector. Lastly, in Aim 3, I will examine changes in NPY and Y1R levels, and co-expression with CRF, after multiple cycles of binge-like ethanol drinking in male and female mice. Binge-induced plasticity in the NPY system that are sex- dependent are predicted, and will be assessed using immunohistochemistry, Western Blots, and real-time PCR to quantify protein and mRNA in the CeA. Taken together, these results will provide new insights into the neurocircuitry underlying sex-differences in binge-like ethanol intake.
