ANTIBODY TO NEURAL CELL-ADHESION MOLECULE CAN DISRUPT THE MIGRATION OF LUTEINIZING-HORMONE-RELEASING HORMONE NEURONS INTO THE MOUSE-BRAIN

The neurons which synthesize and release luteinizing hormone-releasing hormone (LHRH), are hypothesized to originate in the epithelium of th e medial olfactory pit and to migrate into the brain along a scaffoldi ng made up of neural cell adhesion molecule (NCAM)-immunoreactive bran ches of the terminal and vomeronasal nerves. These LHRH neurons, studi ed by immunocytochemical and autoradiographic procedures, were found t o originate within a very short period of embryogenesis, specifically day 10, in mice, and to follow a remarkably ordered spatiotemporal cou rse along the migration route into the brain. The purpose of the prese nt experiments was to determine whether perturbation of the NCAM-immun oreactive migration route, at a particular time in development, would arrest the migration of LHRH neurons into the brain. We found that a 1 mu l injection of antiserum to NCAM into the area of the olfactory pi t, on day 10 of embryogenesis, significantly reduced the number of LHR H-immunoreactive neurons seen in the epithelium of the medial olfactor y pit, with a concomitant significant reduction in the number of LHRH- immunoreactive cells seen outside of the placode, on the migration rou te. These results confirm our initial hypothesis that LHRH neurons mig rate from the epithelium of the olfactory pit to the brain and indicat e that NCAM plays a causal role in this phenomenon. (C) 1994 Wiley-Lis s, Inc.