Evidence that ethanol intake and its abuse have become prevalent among children in their developing years of adolescence and earlier has been accompanied by suggestions that these early experiences may be precursors of ethanol abuse in adulthood. There is, in addition, increasing evidence that experiences with ethanol prior to adolescence or even preadolescence - - beginning sometimes in infancy and continuing thereafter -- is present in some cultural circumstances and could contribute to the child's responsiveness to ethanol as an adolescent and adult. Preliminary research with animal models has yielded experimental evidence that responsiveness to ethanol is affected by early ethanol experience in a variety of forms, but the permanence and scope of these effects remain unclear. The primary aim of the present proposal is to establish the characteristics of early experience that contribute to later responsiveness to ethanol, including: the nature of the consequential effects on responsiveness to ethanol; the duration of these effects; and the features of early experience responsible for these effects. The early experience treatments to be tested are weighted heavily by their potential for associative influences (although nonassociative effects may also be determined) during each of three postnatal periods intended to model early childhood, preadolescence and adolescence in humans. Initial emphasis is on the """"""""early childhood"""""""" stage, which also has seemed in preliminary studies with the rat to be a period of special responsiveness to ethanol -- postnatal days 8-16. With experimental designs intended to determine the contributions of early associative and nonassociative experience with ethanol, as well as general stress, separate studies will assess the influence of early exposure to ethanol odor, ethanol intake during nursing, free ingestion of ethanol, and response-contingent ingestion of ethanol. The consequences of these early experiences will be assessed during periadolescence and adulthood. The experimental designs also include systematic assessment of the influence of associative and nonassociative exposure to ethanol during a """"""""preadolescent"""""""" period (postnatal days 22-24) and during the periadolescent period (postnatal days 30-42) on responsiveness to ethanol in adulthood. Responsiveness to ethanol will be determined with six modes of assessment applied in separate experiments: orienting and habituation to ethanol's sensory effects (to the odor of ethanol and to intraoral infusions of ethanol, measured in terms of change in heart rate or mouthing); strength of acquisition of a conditioned taste aversion,with ethanol as the unconditioned stimulus; the effects of ethanol on sensory preconditioning; free consumption of ethanol; and operant responding for ethanol. Responsiveness to ethanol using these procedures will be measured at one of three ages in the rat corresponding to near the time of weaning, periadolescence, and adulthood. Although this proposal does not directly address neural or physiological mechanisms that might mediate responsiveness to ethanol, it is hoped that productive hypotheses about these underlying mechanisms will emerge from the discovery of clearer relationships between early experience and later responsiveness to ethanol.
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