Effect of prenatal ethanol exposure on response to abrupt reward reduction

Effects of prenatal alcohol exposure on serial pattern performance in the rat

The effect of prenatal alcohol exposure on serial-pattern learning was investigated in adult rats. Pregnant dams were administered a liquid diet which contained 35% ethanol-derived calories (35% EDC) on days 6-20 of gestation. Two control groups were included: a liquid diet control which was pair-fed and had sucrose substituted for ethanol (0% EDC); and a group fed standard lab chow throughout pregnancy. Offspring from each of these prenatal groups were trained to run a straight alley for food pellets. Pellet amount on successive trials was 14, 7, 3, 1, 7. Subjects were exposed to this pattern four times a day for 8 consecutive days. The mean latency to enter the goal-box for the four trials that comprised a monotonically decreasing series of pellet amounts (14, 7, 3, 1) was indirectly related to pellet amount. The mean latency on each trial and the degree of change in running speed across trials was found to be directly related to in utero alcohol exposure. Alcohol exposed offspring demonstrated less change in latencies over trials than controls. Also, the mean latency on the last trial for 7 pellets was shorter than that seen on the previous trial (1 pellet) and similar to that seen after the first trial in which 7 pellets were available. This indicated that satiation was not a factor in the increasing latencies. These data indicate a deficit in serial pattern performance as a function of prenatal alcohol exposure similar to what is observed in children with FAS.

Effects of prenatal ethanol exposure on learned persistence and hippocampal neuroanatomy in infant, weanling and adult rats

The present experiment examined whether deficits in learned persistence, previously seen in 15-day-old infant rats prenatally exposed to ethanol, would be present in weanling and adult animals. Three prenatal treatments, EtOH, PAIR-FED, and LAB CHOW, were combined factorially with partial (PRF) or continuous (CRF) reinforcement training followed by extinction, at 21 days or 6 months of age. The results at 21 days were virtually the same as our earlier findings for 15-day-olds: we did not find the higher level of persistence in PRF-trained EtOH pups relative to CRF-trained EtOH pups, which characterizes the partial reinforcement extinction effect (PREE). The EtOH-PRF and EtOH-CRF animals extinguished at about the same rate, both faster than PRF controls. However, when tested as adults, the EtOH-exposed animals showed a normal PREE, with no deficits relative to controls. An analysis of CA1 pyramidal cells in midtemporal hippocampus demonstrated no significant differences in cell density or in CA1 area among the 3 prenatal diet conditions; however, there was a significant reduction in cell density with age for all groups. These results suggest that a developmental delay, unrelated to these neuroanatomical measures, is responsible for the lack of persistence in young rats exposed prenatally to ethanol.

Effects of prenatal ethanol exposure in C57BL mice on locomotor activity and passive avoidance behavior

The purpose of this study was to examine the long-term behavioral effects of prenatal ethanol exposure in C57BL mice. Pregnant mice received free access to a liquid diet containing 25% ethanol-derived calories (EDC) from gestation days 6 to 18. Control animals were pair-fed an isocaloric 0% EDC diet during the same period of time. An additional control group was included that was maintained on standard lab chow and water throughout pregnancy. At 30 days of age, female offspring were tested for spontaneous locomotor activity in an open field under two lighting conditions (dim or bright illumination). Male offspring were tested in a passive avoidance task at 25 days of age. The activity results demonstrated that the 25% EDC female progeny were more active than controls. This hyperactivity was observed under both lighting conditions, despite the fact that all groups evidenced suppressed activity when tested under bright lights. With regard to passive avoidance behavior, male EtOH-exposed offspring required a greater number of trials to reach criterion than controls. Additionally, they exhibited shorter latencies to enter the shock-associated chamber after receiving a single shock. Taken together, these results confirm our previous findings and demonstrate that C57BL mice are sensitive to both the deleterious behavioral and morphological consequences of prenatal ethanol exposure.