Early postnatal diazepam exposure facilitates maternal behavior in virgin female rats.

Virgin female rats do not display maternal behavior if they are not exposed to the pups during several days. This exposure is called induction. In this work we have studied the effects of early postnatal (PO-P16) diazepam (DZ) administration (1 and 2.5 mg/kg, SC) on the display of maternal behavior of virgin female rats when adults. Although we did not find statistically significant differences between P0-P16 DZ treated and control females with respect to the latency of retrieval, P0-P16 DZ administration resulted in a statistically significant increase of the percentage of female rats that became maternal, showing retrieval behavior. This early postnatal treatment with DZ also increased other variables that are currently measured in maternal behavior tests, such as: time of physical contacts, grooming, crouching, and nest building quality. No statistically significant differences were found in the body weight of treated versus control animals during development, nor during adulthood. Our results provide further evidence that the GABAA-BDZ-Cl- receptor complex is implicated in the development of maternal behavior in female rats.