Molecular Mechanisms of Ethanol Reinforcement

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DESCRIPTION (provided by applicant): Alcoholism is a complex neuropsychiatric disorder that is characterized by periods of chronic drinking, abstinence and relapse. Emerging evidence suggests that ethanol and other drugs of abuse may produce adaptive changes in cell signaling and gene transcription pathways that lead to enduring changes in brain function. These adaptations are thought to regulate behavioral pathologies that occur in alcoholism and are of fundamental importance for treating the alcoholic in the clinic. The preclinical studies in this application are focused on calcium/calmodulin-dependent protein kinase II (CaMKII) as a novel molecular mechanism of alcohol-related behavioral pathologies. We have discovered that voluntary alcohol drinking increases CaMKII1 protein expression in mouse amygdala and that reinstatement of alcohol-seeking behavior is associated with increased CaMKII activation in the lateral amygdala, a sub-nucleus of the amygdala where CaMKII is known to regulate associative learning. These findings suggest the primary hypothesis of this application: voluntary alcohol self- administration and abstinence lead to adaptations in CaMKII signaling that functionally regulate behavioral pathologies associated with alcoholism, such as relapse. The studies in this application have three separate but integrated Specific Aims. First, experiments will elucidate molecular and cellular neuroadaptations in CaMKII that are associated with chronic voluntary alcohol drinking and abstinence. These studies will provide novel information on the effect of voluntary drinking on this key molecular pathway throughout the brain. Second, studies will investigate the functional neural circuitry of CaMKII regulation of alcohol reinforcement. This will be accomplished using a behavioral pharmacology approach coupled with brain site-specific microinjection of specific CaMKII inhibitors. These studies will establish a direct link between CaMKII activity and the reinforcing effects of alcohol that maintain chronic drinking. Third, experiments are proposed to characterize CaMKII regulation of relapse-like behavior using a mouse model of reinstatement of alcohol-seeking behavior. Thus, these studies examine CaMKII regulation of behavioral processes that are fundamental to the development and progression of alcoholism. A better understanding of the molecular and cellular mechanisms that regulate behavioral pathologies in alcoholism has the potential to lead to new pharmacotherapeutic strategies.