After trauma to the nervous system, the peripheral nervous system and the central nervous system (CNS) behave differently from each other. In the peripheral nervous system, regenerative sprouts often elongate and grow over long distances to reestablish functional connections. In the CNS, regenerative sprouts do not elongate beyond 1 mm. Tissue culture and biochemical experiments have demonstrated the presence of inhibitors of neurite growth, proteins with molecular weights 35 and 250 kDa (NI-35, NI-250) which exclusively occur in CNS myelin. Their neutralization leads to long-distance fiber regeneration in spinal cord and brain of the rat.
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