Signals Blocking Axonal Regeneration

It is not the lack of neurotrophins, rather the presence of regeneration inhibitors in myelin and glial scars that effectively negate axonal regrowth (McGee and Strittmatter, 2003). Several myelin-derived proteins have been identified as components of CNS myelin, which prevents axonal regeneration 

named by Mardn Schwab of Zurich University, is a member of the endoplasmic redculum associated protein family, redculon. Despite being associated with endoplasmic redculum of oligodendrocytes, Nogo-A is also exhibited on the surface and mediates growth cone collapse (Fournier et al., 2002). 

Myelin-associated glycoprotein (Mag), belonging to immunoglobulin superfamily, is a potent inhibitor of post-mitodc neuronal outgrowth. There are tw o isoforms of this inhibitor that differ only in their cytoplasmic domain. Ability of Mag to bind sialic acid, although not essendal for its inhibitory effect, potendates it nonetheless (De Bellard anclFilbin, 1999). 

In adcUdon to myelin, inhibitory signals also arise from ghal scars. Proteoglycans are the main culprit in this regard. AdcU-donally, certain proteins present in the scar, like ephrin-B2 and Sema3, also repel the growth cone (Silver and Miller, 2004). 

Inhibitory Signaling from Recep tor Trio NgR-Lingol-p75NTR 

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