Differential effects of prenatal exposure to alcohol on activity and circling behavior in rats

The effects of prenatal exposure to alcohol on behavioral correlates of catecholaminergic function were examined in three experiments. In each experiment, subjects had one of 3 prenatal treatment histories: prenatal alcohol-exposed (35% ethanol-derived-calories, 35% EDC), nutritional control (0% ethanol-derived calories, 0% EDC) or standard control (lab chow, LC). In the first experiment, juvenile (33 to 59 days of age) female rats were tested for 16 hours overnight in standard rotometers. Subjects in the 35% EDC group were more active compared to both control groups, who did not differ from each other. However, the degree of circling (rotation) was not altered by prenatal exposure to alcohol. Since there was a positive correlation between age and rotation in the LC group, but not in the other 2 groups, adult female rats were similarly tested overnight in the rotometer. Again, circling behavior was not differentially affected by prenatal exposure to alcohol. Total overnight activity was no longer significantly greater in the adult 35% EDC group, although their initial activity was higher than that of the LC control group. In the third experiment, subjects from Experiment 2 were administered d-amphetamine (1.25 mg/kg) and tested in the rotometer for 1 hour. Both rotation and activity were increased by d-amphetamine, but there was not a significant interaction with prenatal alcohol exposure. Since rotation is a reflection of the intrinsic asymmetry of the nigrostriatal system, these results suggest that prenatal exposure to alcohol does not alter the development of this asymmetry.