Maternally determined susceptibility to D-amphetamine-induced stereotypy in rats.

During the first week after parturition, rat pups were removed and returned to a mother-present nest, were removed and returned to a mother-absent nest, were separated from their mothers by removal of the mothers, or were undisturbed. In adulthood when repeatedly injected with a dose of D-amphetamine which induces progressively higher levels of stereotypy (2.5 mg/kg), only subjects which had been removed and returned to a mother-present nest in infancy showed a retarded rate of increase in stereotypy.