Ethanol and stress effects on monoamine neurotransmission

Wake Forest University Health Sciences, Winston-Salem NC

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Abstract

DESCRIPTION (provided by applicant): The overall strategy of the INIA-Stress consortium is to take a cross-species approach to define adaptations of the cortical-limbic-HPA axis produced by excessive alcohol exposure as a platform for studying the reciprocal relationship between stress and excessive drinking. This project proposes to define the status of monoamine neurotransmission and GABAergic neuroactive steroid responsivity in key brain structures involved in stress, motivation, reinforcement and ultimately the regulation of excessive ethanol drinking. It will serve as one node for comparison of monkey and mouse tissues, with microarray, genetic, electrophysiology and HPA axis measures serving as other nodes. The overarching hypothesis of this project is that chronic ethanol exposure produces monoamine system adaptations which reduce activity during abstinence, leading to a state of low monoamine function which would produce dysphoria and potentially a drive to consume alcohol. Further, we predict that these adaptations are exacerbated by subsequent exposure to stress. Of particular interest is the novel finding that KORs become supersensitive during chronic ethanol exposure, especially given the efficacy of naltrexone, a non-selective opioid receptor antagonist, in treating alcoholism. Four aims are proposed, including 1) DA changes after chronic intermittent ethanol (CIE) exposure in mice and monkeys 2) CIE followed by forced swim stress in mice 3) Monoamine tissue levels in mice and monkeys and 4) GABAergic neuroactive steroids response to CIE and stress. These aims will provide a comprehensive assessment of monoamine changes induced by chronic ethanol exposure and the differential impact of a stress challenge on a background of chronic ethanol adaptations.