PROJECT SUMMARY Over 16 million people in the United States are diagnosed with Alcohol use disorder (AUD) each year. AUD is characterized by compulsive alcohol use, loss of control over intake, and negative emotional states during periods of withdrawal. The long-term success of current treatment strategies for AUD is low, emphasizing the need for new approaches to treat a broader patient population. The premise of my research is that by better understanding the cellular and molecular mechanisms in the brain that regulate alcohol consumption and reward, new or improved therapeutic strategies for treatment of AUD can be envisioned and developed. My project will investigate the influence of an inhibitory G protein-dependent signaling pathway on alcohol consumption and reward. Baclofen, a GABAB receptor (GABABR) agonist, decreases AUD-associated symptoms in preclinical and clinical settings. In rodents, baclofen suppresses consumption and reward when administered either systemically or directly to the ventral tegmental area (VTA), a key reward-related brain region. The output of VTA dopamine (DA) neurons, the largest sub-population of neurons in the VTA, is moderated by inhibitory G protein-dependent signaling pathways, including signaling mediated by GABABR. Additionally, different proteins, including Regulator of G protein Signaling (RGS) proteins, act to modulate GABABR-dependent inhibition. The AIMS of my project are to probe the impact of GABABR-dependent signaling in VTA DA neurons on alcohol-related behavior (AIM 1), and to Identify the role of R7 RGS proteins in GABABR-dependent signaling in VTA DA neurons (AIM 2). My working hypothesis is that GABABR-dependent signaling in VTA DA neurons suppresses alcohol consumption and reward, and that this signaling pathway is subject to negative regulation by a specific subtype of RGS protein, RGS6. I propose to test this hypothesis using CRISPR/Cas9-mediated gene ablation targeting VTA DA neurons, in addition to ex vivo slice electrophysiology and behavioral analysis. Successful completion of this proposal will improve our understanding of the role that GABABR-dependent signaling in VTA DA neurons plays in alcohol consumption and reward, and reveal whether pharmacologic or genetic enhancement of this inhibitory signaling pathway holds promise as a novel approach to treat aspects of AUD. Knowledge gained in this effort will help inform the improvement of treatment and prevention of AUD.