▪ REVIEW The Role of Schwann cells in Neural Regeneration

The difference in regenerative capacity between the PNS and the CNS is not due to an intrinsic inability of central neurons to extend fibers. Rather, it is probably related to the environment in the CNS that is either repulsive to axonal outgrowth and/or nonsupportive of axonal elongation. In contrast, the PNS both supports and allows for axonal elongation after injury. The Schwann cell, which is the glial cell of the PNS, is strictly required for peripheral regeneration. Here we discuss recent work describing the biology of Schwann cell-dependent regeneration, discuss what is known of the molecular basis of this phenomenon, and how it might apply to the damaged CNS. NEUROSCIENTIST 5:208-216, 1999 KEY WORDS Schwann cell, Regeneration, Axon, Basal lamina, Spinal cord Regeneration is a hallmark of the peripheral nervous sys-tem (PNS). This implies that after mechanical transec-tion, regenerating PNS axons are capable of both finding their original target tissues and re-establishing functional synapses with a high degree of fidelity. In addition, the Schwann cells that were present before injury elaborate new myelin sheaths around the regenerated axons. Th