Effects of neuroleptics administered to lactating rats on the behavioral development of offspring.

Effects of diazepam (DZP) and haloperidol (HAL) given to nursing mothers from the day after delivery to weaning on the behavioral development of their pups were investigated. Weight gain in the pups of mothers that received these drugs did not differ from that in the control pups. Male and female pups exposed to HAL through the milk showed an increase of aggressive behavior (attacking and pinning play) when examined within the social unit of the colony at 4 weeks of age. Although an age-related decrease in this play was observed in the pups of all groups at 7 weeks of age, HAL exposed male and female pups or DZP exposed female pups showed this play more frequently than control pups. At 5 weeks of age, male and female pups exposed to DZP or HAL showed an increase in central ambulation of open-field, in spite of no change in total ambulation. Female pups exposed to DZP or HAL showed an increase of rearing. Female pups exposed to DZP or HAL took more time to reach the goal and made more errors in the maze test at 13-15 weeks of age. Male pups exposed to DZP or HAL showed a decrease in the number of complete mounts. Female pups exposed to DZP or HAL showed a decrease in the number of complete lordoses and an increase in the number of defensive behavior. These results indicate that neuroleptics administered to the dams appear to modify the functioning development of the brain in their offspring.