Failure to restore vision after optic nerve regeneration in reptiles: interspecies variation in response to axotomy.

摘要: Optic nerve regeneration within the reptiles is variable. In a snake, Viper aspis, and lizard Gallotia galloti, slow, although some retinal ganglion cell (RGC) axons eventually reach visual centers (Rio et al. [1989] Brain Res 479:151–156; Lang [1998] Glia 23:61–74). By contrast, in lizard, Ctenophorus ornatus, numerous RGC regenerate rapidly to centers, but unless animals are stimulated visually, regenerated projection lacks topography remain blind via experimental eye (Beazley [2003] J. Neurotrauma 20:1263–1269). V. G. C. ornatus belong respectively Serpentes, Lacertidae, Agamidae Eureptilia, major modern group of living comprising Squamata (snakes, lizards, geckos) Crocodyllia. Here we have extended findings on Eureptilia include two geckos (Gekkonidae), Cehyra variegata Nephrurus stellatus. We also examined turtle, Chelodina oblonga, Testudines being sole surviving representatives Parareptilia, more ancient reptilian group. all three species, visually elicited behavioral responses were absent throughout regeneration, result supported electrophysiologically; axonal tracing revealed that only small proportion crossed lesion none entered contralateral optic tract. failed chiasm variegata, N. stellatus opposite nerve; limited ipsilateral was seen variegata. Our results support heterogeneous response axotomy reptiles, each which nevertheless dysfunctional. Comp. Neurol. 478:292–305, 2004. © 2004 Wiley-Liss, Inc.