Some effects of prenatal exposure to d-amphetamine sulfate and phenobarbital on developmental neurochemistry and on behavior.

Amphetamine. Prenatal intraperitoneal injection of d-amphetamine sulfate (5 mg/kg) produces decreases in the levels of catecholamines in the brain the day of birth and increases on day 30. Open-field activity from days 12 to 31 was higher for the group of animals injected with amphetamine or saline if scores were totaled across all test days. At day 75 the offspring of amphetamine-injected mothers exhibited altered open-field behavior. The effects were not observed with subcutaneous injection regardless of the dose used (2.5, 5.0, and 10.0 mg/kg). The lowest subcutaneous dose decreases neonatal viability. Phenobarbital. Prenatal intraperitoneal injection of phenobarbital (80 mg/kg) resulted in decreased litter size, increases mortality, and decreased amounts of nucleic acid and protein in the brains of surviving offspring. Behavioral deficits associated with response perseveration could be demonstrated at 60 days in the mice prenatally exposed to this dosage. Subcutaneous injections of phenobarbital to pregnant mice at 80 and 40 mg/kg, but not 20 mg/kg, doses increased neonatal mortality. Mature animals prenatally exposed to 40 mg/kg phenobarbital have altered open-field behavior and differ from control animals on a passive avoidance task. Mature offspring prenatally exposed to the 20 or 40 mg/kg dose also responded less than controls on an operant task requiring an increasing number of responses per reinforcement. These studies suggest that prenatal exposure to phenobarbital has in some way altered the animals' reactivity to stimualtion.