INFANTILE BEHAVIORAL SENSITIVITY TO ETHANOL AS A FUNCTION OF LATE PRENATAL EXPOSURE TO THE DRUG

ARIAS, C.; MLEWSKI E.C.; SPEAR, N.E.; MOLINA, J.C.

Chicago, Illinois, EEUU

Congreso; 2007 Annual Meeting of the Research Society on Alcoholism.; 2007

Research Society on Alcoholism

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 ethanol’s positive reinforcing effects. The present study examine the effect of prenatal ethanol exposure on the infantile behavioral sensitivity to different ethanol doses known to exert biphasic motivational effects (appetitive and aversive). 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 three 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 reached peak values and were 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) Independent of prenatal treatment, infants exhibited acute tolerance to ethanol’s 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 or acute sensitivity and tolerance to ethanol doses that exert biphasic locomotive effects.