The purpose of this project is to determine factors which aid nerve fiber regeneration. In the present study we have examined the binding pattern of fluorescin-labeled lectins to nerve. Lectins are substances which bind specifically to the sugar portion of glycoconjugates and therefore can be used to detect cell surface and extracellular matrix molecular changes that occur during nerve degeneration and regeneration. In normal rat nerve, the lectins Concanavilin, Maclura and Wheat germ bound to the perineurium and basement membrane of endoneurial Schwann cells and blood vessles. Soybean agglutinin stained the endothelium throughout the nerve. Dolichos, Peanut and Griffonia attached only to the perineurium. Because of a turnover in laboratory personnel his experiment was interrupted. However, with arrival of new investigators, the binding of lectins during peripheral nerve regeneration will be undertaken and observations exended to the central nervous system. We especially want to examine the transition zone between the peripheral and central nervous system to determine why regeneration ceases at this region when nerve grafts are used to promote nerve fiber regeneration.