DEVELOPMENT OF NADPH-DIAPHORASE EXPRESSION IN CHEMOSENSORY SYSTEMS OFTHE OPOSSUM, MONODELPHIS-DOMESTICA

Using NADPH-diaphorase histochemistry, the present study describes dev elopment of olfactory and vomeronasal systems in postnatal opossums, M onodelphis domestica. NADPH-dependent staining is absent at and around the time of birth. By 2 weeks of age and through adulthood, intense s taining is seen along the luminal surface of the olfactory epithelium (OE) and of the vomeronasal sensory epithelium (VNE), as well as in Bo wman's glands of the OE. Staining of the adult VNE is not homogeneous; it is restricted to the superficial 2/3 of the epithelium. At 2 weeks of age, staining in the brain is seen only at the surface of the vent ricles and in blood vessels. At 1 month of age and through adulthood, staining: of varying intensity is seen in individual olfactory bulb gl omeruli, although the incoming olfactory axons are relatively unstaine d. Interestingly, whereas at 30 days of age, staining of the accessory olfactory bulb (AOB) glomeruli is uniform, 2 weeks later and in the a dult, NADPH staining is concentrated in the rostral half, with little or no staining observed in the posterior portion. Darkly stained perig lomerular cells are seen throughout the extent of the differentially-s tained glomerular layer. From 30 days of age and through adulthood, in tense NADPH staining is also observed in the islands of Calleja, as we ll as in cells of the dorsal cortex, often associated with the path of the rostral migratory stream. (C) 1998 Elsevier Science B.V. All righ ts reserved.