Neuropharmacology of Ethanol Reinforcement

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DESCRIPTION (provided by applicant): Alcoholism is a chronically relapsing disorder characterized by a compulsion to seek and take alcohol and has been linked to dysregulation of the brain arousal and emotional systems critically involved in both the positive and negative reinforcement important for the development of alcoholism. Dependence and the vulnerability to relapse has been argued to include counteradaptive neurochemical events within the brain emotional systems normally used to maintain emotional homeostasis (Koob and Le Moal, 2005, 2008, Appendix) and produce compulsive drinking via negative reinforcement mechanisms. In the previous funding period, we characterized key roles of increased activity of the brain stress systems corticotropin-releasing factor (CRF) and norepinephrine and decreased activity in the neuropeptide Y anti-stress system in dependence-induced drinking. The research plan of the present competitive renewal will be to continue the studies on the mechanisms of neuroadaptation within brain arousal-stress systems during the development of excessive drinking induced by dependence with a focus on newly identified brain arousal-stress systems within the neurocircuitry of the extended amygdala: vasopressin, hypocretin (orexin) and nociceptin. The overall hypothesis under test in the present proposal is that increased vasopressin and hypocretin activity and decreased nociceptin activity in the central nucleus of the amygdala and/or basolateral amygdala, bed nucleus of the stria terminalis, and nucleus accumbens are responsible for the enhanced drinking associated with a dependence, and that these systems interact via an activation of CRF in the extended amydala. The Specific Aims are: To explore the role of vasopressin (SpA 1), orexin (SpA 2), and nociceptin (SpA 3) in the extended amygdala on increased ethanol self-administration during withdrawal in rats using administration of selective antagonists/agonists, and to explore the role of corticotropin releasing factor (CRF) in the actions of vasopressin, orexin and nociceptin in rats during dependence (SpA 4). To accomplish these aims, a series of studies with administration of selective receptor subtype antagonists and/or agonists in rats and neuroanatomical studies with measures of neuronal activation (cFos) using a reliable animal paradigm of excessive ethanol self-administration in dependent rats will be employed. Results will provide novel and innovative insights into the neural substrates of emotional dysregulation in key brain motivational areas that form the basis of excessive drinking associated with dependence, and as such, will provide new targets for diagnosi of vulnerability, prevention and treatment of alcohol dependence. PUBLIC HEALTH RELEVANCE Alcoholism produces an enormous cost to United States society of over 200 billion dollars per year when considering direct pathology, indirect medical and social consequences and loss of productivity. Alcoholism is a chronically relapsing disorder characterized by a compulsion to seek and take alcohol and has been linked to dysregulation of the brain arousal and emotional systems critically involved in the development of dependence on alcohol. The studies outlined in the present proposal will identify novel neurochemical mechanisms involved in the perturbations of these brain emotional systems that produce dependence on alcohol. Results will provide novel and innovative insights into the neural substrates of emotional dysregulation in key brain motivational areas that form the basis of excessive drinking associated with dependence, and as such, will provide new targets for diagnosis of vulnerability, prevention and treatment of alcohol dependence.