Abstract
During the development and regeneration of the nervous system, cell adhesion molecules have been implicated in the guidance of migrating neurons and the routing of growing axons. Recent advances have been made in understanding the molecular basis for neuron-neuron and neuron-glial adhesion. These findings have raised new questions concerning the respective contributions to axon outgrowth that are made by the different identified cell adhesion molecules. We have been studying how two cell adhesion molecules, the 8D9 antigen (which is similar or identical to the glycoproteins described by other investigators as NILE, L1, and Ng-CAM) and N-CAM function in neuron-neuron and neuron-glial interactions that result in neurite extension. We have evidence that indicates that the 8D9 antigen plays a vital role in neurite outgrowth and could play an essential part in promoting both peripheral and central nervous system regeneration. N-CAM appears to be a less effective substrate but the function of N-CAM in this process may be heavily dependant on the precise form of the N-CAM.