1/8: INIA Stress and Chronic Alcohol Interactions: Role of Dynorphin/KOR and Oxytocin Systems in Stress-Enhanced Alcohol Drinking, Relapse, and Impaired Behavioral Flexibility

PROJECT SUMMARY Stress is known to be a significant factor in triggering relapse, promoting heavy alcohol (ethanol) consumption, and producing adaptations that reduce behavioral flexibility, thereby compromising control over alcohol drinking and elevating susceptibility to relapse. Unfortunately, mechanisms and neurocircuitry underlying the complex interaction between stress and alcohol drinking are not well understood. As part of the INIAstress Consortium, we developed a mouse model in which repeated brief forced swim stress (FSS) exposure interacts with chronic intermittent ethanol (CIE) exposure to selectively enhance alcohol drinking in dependent (CIE-exposed) mice. During the current funding period we established a role for the pro-stress neuropeptide dynorphin/kappa opioid receptor (DYN/KOR) system in stress-enhanced alcohol drinking. At the same time, we used operant conditioning procedures to demonstrate that the anti-stress neuropeptide oxytocin (OT) reduced alcohol self- administration and stress-induced relapse-like behavior. This research project focuses on the role of DYN/KOR and OT systems within stress-relevant circuits in models demonstrating the ability of stress to interact with chronic alcohol in promoting escalation of alcohol drinking, enhanced relapse-like behavior, and impaired behavioral flexibility. The project will employ two stressors (forced swim stress (FSS) and predator odor (TMT) exposure), two models of stress-alcohol interactions (CIE-FSS Drinking and stress (TMT)-induced operant alcohol relapse seeking/drinking), and two measures of behavioral (in)flexibility (alcohol-biased choice behavior and persistence of alcohol drinking despite aversion). Building on our previous work demonstrating an important role for DYN/KOR activity in the central amygdala (CeA) and pilot data showing strong DYN input to the CeA from the insular cortex (a stress and alcohol sensitive cortical area), studies will examine the role of DYN/KOR signaling in insular cortical (IC) projections to the CeA (IC-CeADYN pathway). Other pilot data suggest that the stress-buffering effects of OT may be mediated by signaling in the CeA. Thus, studies will examine OT activity in hypothalamic (PVN) projections to the CeA (PVN-CeAOT pathway). Further, studies will examine the potential unique interactive effects of the DYN/KOR and OT systems in the PVN on behavioral consequences of stress-alcohol interactions. The general experimental strategy will entail utilizing transgenic mice and pharmacological, chemogenetic, and CRISPR/Cas9 approaches to target manipulation of these neuropeptides in specific neurons within these specific neurocircuits. Collectively, these studies focus on adaptations in pro-stress (DYN/KOR) and anti-stress (OT) systems within stress-relevant neurocircuits using different stressors and different drinking models, thereby directly interfacing with the overall thematic framework of the consortium. The ultimate goal is to gain new knowledge that will inform development of more effective interventions for treating stress-related excessive alcohol drinking and relapse.