FACTORS AFFECTING THE ONSET OF EXCESSIVE ETHANOL INTAKE

Winston-Salem State University, Winston Salem NC

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Abstract

DESCRIPTION (provided by applicant): The major aim of the proposed research is to continue to investigations toward developing an alternative model of excessive ethanol (EtOH) consumption in an inbred rat strain (MR) that was selected for differences in stress reactivity. The PI will conduct experiments that follow directly from past work in this laboratory, and will engage in experiments in the operant self-administration paradigm whereby rats will work to obtain EtOH (10% concentration) during limited time periods. The latter experiments represent a new direction in the PI's research experience, and will serve to significantly enhance his professional development by preparing the PI for more opportunities for collaboration with a large Alcohol Center at a neighboring institution. Furthermore, the proposed work will serve to enhance the research careers of undergraduates working in this laboratory. Because some of the current work on rat genetic models of alcoholism does not usually address the strong environmental influences on whether a genetic trait for EtOH abuse is expressed, and often do not include female subjects in their studies, there is a need for a rat model where there is an apparent susceptibility to excessive EtOH consumption, but where the trait occurs only in specific contexts and where sex differences are considered. The experiments included here will (1) examine environmental factors needed for the expression of a high intake of EtOH in MR rats by manipulating specific amounts of EtOH during a pre-exposure period and by manipulating the interval of time between pre-exposure and later voluntary consumption of EtOH; (2) will systematically study MR rats (vs. MNRA and a control strain) in the sucrose-substitution method for developing EtOH self-administration, and will include a comparison of sex differences. Follow-up experiments will examine the pattern of EtOH intake as it relates to appetative and consummatory factors which affect an EtOH intake bout. Finally, experiments will be conducted on the alcohol-deprivation-effect (ADE) where rats show a temporary increase in EtOH intake following a period of abstinence. This will be studied in MR rats that have a brief history of high or low EtOH consumption, have different access histories to EtOH, and have repeated periods of deprivation. This phenomenon will be examined in both sexes and in an operant context as well as in a continuous homecage access context. Results of these experiments should open new research paths using the operant methodology for the PI, and the results may also answer whether the MR rat strain is a plausible model for studying the relationship between genetic stress-susceptibility and variation in excessive EtOH consumption.