CNS Myelin: Does a Stabilizing Role in Neurodevelopment Result in Inhibition of Neuronal Repair after Adult Injury?

Abstract

The inhibitory properties of mature oligodendrocytes and CNS myelin for neurite outgrowth were clearly documented more than a decade ago in studies involving co-cultures of dissociated glial cells and neurons. Since then, in vitro and in vivo studies have begun to characterize some of the CNS myelin-associated inhibitors of neurite growth. Furthermore, experimental techniques for neutralizing or suppressing these inhibitory effects have been developed. The results of several experiments, involving the suppression of myelination in the developing or adult CNS, suggest that the relatively late appearance of CNS myelin during neural development may serve to stabilize and restrict axonal outgrowth (e.g., collateral sprouting) after appropriate axonal connections have been established. This suggested developmental role of myelin may consolidate and limit the degree of axonal plasticity within the adult CNS; consequently, however, it might also limit axonal regeneration after injury.