Repeated exposure to moderate doses of alcohol in the rat fetus: evidence of sensitization to toxic and chemosensory aspects of alcohol.

Two experiments tested responsiveness of the rat fetus to alcohol on gestational day (GD) 20 after previous maternal administration of low-to-moderate doses of alcohol (1 or 2 g/kg during GDs 17 to 19). Maternal alcohol intoxication on GD 20 resulted in substantial suppression of spontaneous fetal motor activity. The analysis of mouthing movements showed that this suppression of movement was further enhanced by exposure to alcohol during the previous 3 days of gestation (GDs 17 to 19). A second experiment indicated that this same exposure to alcohol during GDs 17 to 19 induced fetuses on GD 20 to emit more mouthing movements in response to intraoral infusions of alcohol. A moderate amount of prenatal alcohol exposure apparently sensitizes the fetus to the pharmacological and orosensory effects of alcohol.