Proliferation and migration of receptor neurons in the vomeronasal organ of the adult mouse

Cell proliferation and differentiation in the vomeronasal organ of the adul t mouse was studied by bromodeoxyuridine (BrdU) immunohistochemistry couple d to immunostaining for specific markers of the differentiation, such as ca rnosine, B50-GAP43 (growth-associated protein) and stathmin. The present st udy shows that three populations of proliferating elements are present in t he vomeronasal sensory epithelium that are placed, respectively, in the sup porting cell layer, at the boundaries between the sensory epithelium (S-VNO ) and the non-sensory (NS-VNO) and in the basal region of the S-VNO. The nu mber of dividing cells at the boundaries of the S-VNO is by far prevailing. Few proliferating cells located adjacent to the basal membrane are, howeve r, present 1 day after BrdU inoculations. Seven days after BrdU treatment i mmunopositive nuclei were detected in more central regions of the VNO and a t longer survival times they were also positive to carnosine, a marker of f ully differentiated neurons. In conclusion, the present results suggest tha t at least two populations of VNO neuronal precursors are responsible for c ell replacement throughout life. (C) 2000 Elsevier Science B.V. All rights reserved.