EXPRESSION OF POLYSIALYLATED N-CAM IN THE CENTRAL-NERVOUS-SYSTEM OF ADULT CANARIES AND ITS POSSIBLE RELATION TO FUNCTION

Polysialylated neuronal cell adhesion molecule (PSA-N-CAM) is a cell s urface molecule associated with neurons that undergo changes in config uration or spatial translocation. In both cases, this molecule is thou ght to reduce the adhesivity of these cells or of their processes, whi ch can thereby insinuate themselves into the existing parenchyma. We u sed a monoclonal antibody specific to PSA to offer what we believe is the first account of the distribution of PSA-N-CAM in the adult songbi rd brain. This antibody stained a diversity of cell classes and proces ses, as follows: 1) a subset of ventricular zone cells; 2) migrating c ells thought to be neuroblasts; 3) a subset of differentiated neurons; 4) some brain surface astrocytes; 5) some tanycytes; 6) the neuropil of some regions; 7) some axonal fibers; and 8) possibly some synapses. Our results demonstrate also, for the first time, the wide distributi on of a very numerous population of migrating cells in the telencephal on and the seasonal regulation of PSA-N-CAM expression in a part of th e adult brain known to undergo seasonal changes in cell recruitment an d function. However, we did not find PSA-N-CAM associated with young m igrating cells in the high vocal center (HVC), nor was there PSA-N-CAM in the robust nucleus of the archistriatum (RA), which is known to re ceive new axonal endings from HVC. In these instances spatial transloc ation may occur with the assistance of other surface molecules. (C) 19 95 Wiley-Liss, Inc.