Neonatal alcohol exposure produces more severe motor coordination deficits in high alcohol sensitive rats compared to low alcohol sensitive rats.

Prenatal exposure to alcohol can produce a number of behavioral alterations, including hyperactivity, learning deficits and motor impairments. However, the severity and nature of behavioral alterations varies markedly among children of women who drink during pregnancy. One important determinant of this variation may be genetic differences in the response to alcohol. Recently, we demonstrated that exposure to alcohol during development produced hyperactivity in rats bred for high alcohol sensitivity (HAS), but not in rats bred for low alcohol sensitivity (LAS). These lines were selectively bred for extremes in alcohol-induced "sleep time." The present study investigated the effects of ethanol exposure during development on motor coordination later in life in both HAS and LAS rats. Using an artificial rearing procedure, neonatal pups from each line were exposed to a binge-like alcohol treatment on postnatal days (PD) 4-9. Within each line, one group was exposed to ethanol (6.0 g/kg/day), one group served as an artificially reared control, and a third served as a normally reared control group. On PD 30, parallel bar motor performance was evaluated. Exposure to ethanol during development severely impaired motor performance in the HAS rats compared to their controls. In LAS rats, early ethanol exposure produced only mild and nonsignificant effects on motor performance. Thus, HAS rats were more vulnerable to ethanol-induced motor deficits compared to the LAS rats. Importantly, there were no differences in peak blood alcohol level between the lines, indicating that vulnerability to ethanol's teratogenic effects was not due to differences in metabolic rate. These results suggest that genetic differences in response to alcohol may serve as a predictor for susceptibility to ethanol's teratogenic effects.