NI-35/250/nogo-a: A neurite growth inhibitor restricting structural plasticity and regeneration of nerve fibers in the adult vertebrate CNS
The function of the nervous system depends on the highly specific pattern of neuronal connectivity formed between neurons during development. The specificity in proper pathway formation is thought to rely on a number of molecular guidance mechanisms and cues that involve selective adhesion, growth c...
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Veröffentlicht in: | Glia 2000-01, Vol.29 (2), p.175-181 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The function of the nervous system depends on the highly specific pattern of neuronal connectivity formed between neurons during development. The specificity in proper pathway formation is thought to rely on a number of molecular guidance mechanisms and cues that involve selective adhesion, growth cone avoidance, surface gradients, guidepost cells, and chemotropism. Analysis of the molecular basis for these guidance mechanisms showed that the molecules involved often belong to distinct multigene families and that they can provide both short- and long-range attractive as well as repulsive cues. Whereas morphological remodeling of axonal and dendritic trees, shifting and strengthening of synaptic connections as a result of functional activity, appear to be important processes during development, major adaptive changes (structural plasticity) are limited in the postnatal and mature central nervous system (CNS). The reasons for the poor regenerative capacity of injured fiber tracts within the mature CNS of higher vertebrates have been controversial. Two main hypotheses were suggested: the adult CNS may be unable to reinitiate important ontogenic events including the reinitiation of neuronal growth programs and the sufficient upregulation of trophic and tropic factors; alternatively, the presence of neurite growth inhibitory factors may be the reason for the limited structural plasticity and regenerative capacity of the adult vertebrate CNS. It is, however, reasonable to assume that a combination of several factors contribute to the nonconducive environment of CNS tissue. Thus the relative balance of positive versus inhibitory factors may alter the local environment and ultimately influence the degree of successful sprouting and regeneration responses in the CNS. |
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ISSN: | 0894-1491 1098-1136 |
DOI: | 10.1002/(SICI)1098-1136(20000115)29:2<175::AID-GLIA11>3.0.CO;2-F |