ROLE OF POLYSIALIC ACID IN PERIPHERAL MYELINATED AXONS

Polysialic acid (PSA), generally lost from the vertebrate nervous syst em during maturation, may regulate developmental differences in axon g rowth, bundling, and sprouting. Changes in polysialic levels on the ax on surface seem to be involved during development in establishing norm al pattern of muscle innervation. Besides the well-established role of PSA as a regulator of cell-cell interactions during development, PSA expression in myelinated axons may be related to reparative events in response to chemically induced injuries. Histochemical staining method using lectins with well-characterized binding specificities shows tha t glycoconjugates of the node of Ranvier undergo a rearrangement durin g exposure to 2,5-hexanedione, known to induce a peripheral neuropathy characterized by giant axonal swelling and retrograde demyelination. In particular, neutral glycoproteins with terminal galactose are repla ced by sialoglycoproteins, consistent with the proposed role of PSA as a regulator of axonal behaviour during regeneration. (C) 1996 Wiley-L iss, Inc.