Effects of testing age and fostering experience on seizure susceptibility of rats treated prenatally with chlorpromazine.

Offspring of rats treated with 2 mg/kg body weight chlorpromazine (CPZ) on Days 5-8 of gestation had lower seizure thresholds than offspring of saline-treated controls at 30, 60, 90, and 120 days of age. The CPZ-treated offspring were also heavier than controls prior to weaning. Further analysis using cross-fostered litters indicated that at least part of the drug effect on seizure thresholds took place before birth, although a postnatal component was also demonstrated. A striking effect of the fostering experience itself on the seizure threshold prevented conclusions about the relative importance of prenatal and postnatal influences.