NEUROGENESIS AND MIGRATION OF RECEPTOR NEURONS IN THE VOMERONASAL SENSORY EPITHELIUM IN THE OPOSSUM, MONODELPHIS-DOMESTICA

The sensory epithelium of the vomeronasal organ (VNO) contains primary chemosensory receptor neurons that project to the accessory olfactory bulb (AOB). In the present study, neurogenesis and cell migration in the sensory epithelium of the VNO were analyzed in opossums (Monodelph is domestica) by using bromodeoxyuridine (BrdU) labeling. 1) In the VN O of normal adult opossums, BrdU labeled a small number of cells local ized in the basal region of the sensory epithelium. After I or 2 weeks of survival, the labeled cells appeared in the receptor cell layers a nd became receptor neurons, as indicated by coexpression of the G prot eins G(i alpha 2) or G(o alpha). 2) In the VNO in which the receptor n eurons had been destroyed by removing the AOB, the number of BrdU-labe led cells in the reconstituting sensory epithelium was greatly increas ed compared with that in the intact VNO. The labeled cells were also l ocated in the basal region of the sensory epithelium. 3) In the develo ping VNO (at postnatal day 10), more cells in the basal region of the sensory epithelium were labeled than in the adult VNO, indicating rapi d cell proliferation; and there appeared to be more labeled cells in t he basal region near the margins of the sensory epithelium where it me ets the nonsensory epithelium. These observations demonstrate that, in the opossum VNO, there is a population of proliferating cells in the basal region close to the basal lamina in the sensory epithelium. The newly generated neurons in the basal region migrate vertically into th e receptor cell layer. (C) 1998 Wiley-Liss, Inc.