Prenatal alcohol exposure and thermotaxic behavior in neonatal rats.

The effect of prenatal alcohol exposure on thermotaxic behavior was investigated in 5-day-old rat pups. Pregnant dams were administered a liquid diet which contained 35% ethanol-derived calories (35% EDC) on days 6 to 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 (LC) throughout pregnancy. Pups from each of these prenatal treatments were tested on a thermal gradient (thermocline). On each of 5 trails, pups were placed in the cool end of the thermocline and their position along the gradient was measured after 10 min. All prenatal treatment groups displayed thermotaxic behavior by moving towards the warm end. However, pups in the 35% EDC treatment group moved significantly further towards the warm end in the later trials. Despite their position on a warmer surface, their body temperature did not rise concurrently. Thermoregulatory deficits caused by prenatal alcohol exposure might account for these results.