PERINATAL ADMINISTRATION OF DIAZEPAM ALTERS SEXUAL DIMORPHISM IN THE RAT ACCESSORY OLFACTORY-BULB

The present study examines the effects of pre and/or early postnatal a dministration of diazepam on the mitral cell and on the light and dark granule cell populations in the sexually dimorphic accesory olfactory bulb of the rat. Quantitative differences related to sex were observe d in the numbers of the three types of neurons, with vehicle males sho wing greater numbers of cells than vehicle females. The number of mitr al cells in males decreased to the levels shown by female rats followi ng prenatal and pre-postnatal diazepam treatments, whereas the DZ trea tments did not affect the females. In addition, the diazepam administr ation during the prenatal, postnatal and pre-postnatal periods decreas ed the numbers of both light and dark granule cells in males, while th ese two granule cell subpopulations were not affected in diazepam trea ted females. These results indicate that perinatal administration of d iazepam can alter the sexual dimorphism in the accessory olfactory bul b and that the GABA(A)/benzodiazepine receptor complex is involved in the sexual differentiation this part of the brain.