Degeneration and regeneration of ganglion cell axons

Abstract

The retino‐tectal system has been used to study developmental aspects of axon growth, synapse formation and the establishment of a precise topographic order as well as degeneration and regeneration of adult retinal ganglion cell (RGC) axons after axonal lesion. This paper reviews some novel findings that provide new insights into the mechanisms of developmental RGC axon growth, pathfinding, and target formation. It also focusses on the cellular and molecular cascades that underlie RGC degeneration following an axonal lesion and on some therapeutic strategies to enhance survival of axotomized RGCs in vivo. In addition, this review deals with problems related to the induction of regeneration after axonal lesion in the adult CNS using the retino‐tectal system as model. Different therapeutic approaches to promote RGC regeneration and requirements for specific target formation of regenerating RGCs in vitro and in vivo are discussed. Microsc. Res. Tech. 48:55–62, 2000. © 2000 Wiley‐Liss, Inc.

Rearrangement of the retino‐collicular projection after partial optic nerve crush in the adult rat

“…According to the chemoaf®nity hypothesis, the topographical arrangement of retinal projections is established by the spatially segregated expression of targeting molecules in both retina and tectum (Stirling, 1991;Ba Èhr & Bonhoeffer, 1994;Isenmann et al, 2003). The retino-topic map formed between RGC and their target region has served widely as a model system to investigate mechanisms underlying the highly precise organization of axonal connectivity of the nervous system, both during development and after axonal regeneration (Weise et al, 2000;Isenmann et al, 2003).…”

Ectopic expression of transcription factor AP‐2δ in developing retina: effect on PSA‐NCAM and axon routing

“…Unlike fish, adult ganglion cells from mammalian and chicken retina do not regrow their axons after injury to the optic nerve. However, in the absence of their normal environment and/or under the correct permissive cues, axonal regeneration is possible (Weise et al 2000;Koeberle and Bahr 2004). While the mechanisms underlying axonal regrowth remain poorly understood, regrowth is believed to be prevented by inhibitory molecules at the site of injury and/ or lack of positive cues at the cut site (Charalambous et al 2008).…”