PUTATIVE GAP JUNCTIONAL COMMUNICATION BETWEEN AXON AND REGENERATING SCHWANN-CELLS DURING MAMMALIAN PERIPHERAL-NERVE REGENERATION

Gap junctions are intercellular channels which mediate the traffic of ions and a variety of molecular messengers between contiguous cells. H ere, we report on the possibility that atypical gap junctions develop between heterologous tissues, such as regenerating nerve axons and Sch wann cells, during peripheral nerve regeneration in adult rats. After a complete transection and subsequent regeneration in the rat sciatic nerve distal segment, a small scale gap junction-like structure was ob served between the regenerating axons and adjoining Schwann cells, Imm unoelectron microscopy showed that one of the gap junctional proteins, connexin32, was located at a small region of contact between the axon and Schwann cells, Biocytin, a small molecular weight dye, was transp orted from regenerating axons into adjoining Schwann cells. The presen t findings suggest that regenerating axons communicate directly with a djacent Schwann cells through small gap junctions, which may play a ro le in the mechanism of regeneration following nerve transection. (C) 1 998 IBRO. Published by Elsevier Science Ltd.