CONICET | Buscador de Institutos y Recursos Humanos

Exposure to moderate ethanol doses during late gestation in the rat results in subsequent heightened affinity for ethanol ingestion. This treatment also appears to sensitize neonates to ethanols positive reinforcing effects of the state of intoxication. The present study examines infantile behavioral sensitivity to different ethanol doses known to exert biphasic motivational effects (appetitive and aversive) as a function of prior prenatal experiences with ethanol. The design of the experiment was conceived not only to assess acute behavioral sensitivity to ethanol but also to analyze the development of acute tolerance, the impact of pre- and postnatal ethanol administration upon habituation processes and the possible interaction between these phenomena. Pups derived from 27 Wistar dams were employed. During gestational days 17-20 dams received a daily i.g. administration of 0 or 2 g/kg ethanol. At postnatal days 12 and 13 pups received an i.g. administration of 0, 0.5 or 2.5 g/kg ethanol. Locomotion was later assessed in an automated activity chamber. One third of the pups corresponding to each prenatal treatment were evaluated at postadministration times 5-10, 30-35 and 60-65 min. Another third was tested only during the last two postadministration periods while the remaining subjects were only tested at postadministration time 60-65 min. At 30-35 min blood ethanol levels reach peak values and are similar to those attained at 60-65 min. The main results of the study were as follows: a) Pups prenatally treated with ethanol exhibited heightened activity levels particularly following i.g. administrations. b) Behavioral habituation was observed both within and between sessions. This process was not affected by prenatal treatment. c) The 2.5 g/k ethanol dose induced biphasic motor effects (hyperactivity followed by hypoactivity). d) Independently from prenatal treatment, infants exhibited acute tolerance to ethanols sedative properties. e) Blood ethanol concentrations were unaffected by prenatal treatment. These results indicate that moderate exposure to ethanol during late pregnancy sensitizes the organism to mild stressors without affecting non-associative learning capabilities nor acute sensitivity and tolerance to ethanol doses that exert biphasic locomotive effects.

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