EARLY POSTNATAL DIAZEPAM EXPOSURE FACILITATES MATERNAL-BEHAVIOR IN VIRGIN FEMALE RATS

Virgin female rats do not display maternal behavior if they are not ex posed to the pups during several days. This exposure is called inducti on. In this work we have studied the effects of early postnatal (PO-P1 6) diazepam (DZ) administration (1 and 2.5 mg/kg, SC) an the display o f maternal behavior of virgin female rats when adults. Although we did not find statistically significant differences between PO-P16 DZ trea ted and control females with respect to the latency of retrieval, PO-P 16 DZ administration resulted in a statistically significant increase of the percentage of female rats that became maternal, showing retriev al behavior. This early postnatal treatment with DZ also increased oth er variables that are currently measured in maternal behavior tests, s uch as: time of physical contacts, grooming, crouching, and nest build ing quality. No statistically significant differences were found in th e body weight of treated versus control animals during development, no r during adulthood. Our results provide further evidence that the GABA (A)-BDZ-Cl- receptor complex is implicated in the development of mater nal behavior in female rats.