Exposure of rats to alcohol in utero alters drug sensitivity in adulthood.

Pregnant rats were intubated with alcohol (ethanol, 3 grams per kilogram) twice daily throughout gestation. Control animals received solutions of isocaloric sucrose. At birth, offspring were placed with untreated surrogate dams. Beginning at 6 months of age, the offspring were tested for their thermogenic responsiveness to various drugs and to cold. Prenatal exposure to alcohol resulted in tolerance to alcohol and cross-tolerance to pentobarbital and diazepam but did not affect responsiveness to cold. This pattern of effects suggest that prenatal exposure to alcohol produces specific long-term effects on the neural mechanisms underlying drug tolerance.