Sabino, ValentinaCottone, PietroShafique, Samih2023-02-232022https://hdl.handle.net/2144/45658Alcohol use disorders (AUD) are one of the most prevalent psychiatric disorders in the United States, and account for a tremendous burden of spending, morbidity, and mortality every year. While ethanol at first is consumed for its pleasant subjective effects, in the later stages of AUD, drinking alleviates the withdrawal-induced negative emotional state. The recruitment of brain stress response systems in the extended amygdala is responsible for this transition and contributes to the development of addiction. The Bed Nucleus of the Stria Terminalis (BNST) is a brain region within the extended amygdala that undergoes profound neuroadaptations within the context of chronic stress, as well as following chronic ethanol exposure. Pituitary Adenylate Cyclase Activating-Polypeptide (PACAP) and its cognate receptor PAC1R are highly expressed in the BNST and have been proposed as critical regulators of alcohol addiction. We have previously shown that PACAP levels are increased in the BNST following chronic alcohol drinking. The present study sought to characterize the PACAPergic inputs to the BNST that are affected by chronic intermittent alcohol drinking, including those afferents originating from the lateral parabrachial nucleus (LPBn). Using an intermittent access two-bottle choice paradigm in PACAP-Cre mice, we established ethanol dependence and then chemogenetically inhibited afferent PACAP projections to the BNST using an inhibitory retro-DREADD. In a separate C57BL/6J cohort, we processed the LPBn for PACAP immunohistochemistry to assess PACAP levels in ethanol drinking mice versus controls. We found that inhibiting PACAP afferents to the BNST decreases ethanol intake. Additionally, we found increased PACAP immunoreactivity in the LPBn in ethanol drinking mice compared to controls. Finally, we found that PAC1R in the oval nucleus of the BNST is expressed in protein kinase C δ neurons. These data lay the foundation to further investigations into the sources of the PACAP population in the BNST and their exact mechanism of action. These studies are steps forward to development of novel therapeutic targets to combat AUD.en-USNeurosciencesAddictionAlcoholAmygdalaPACAPThesis/Dissertation2023-02-16