Slow recovery of goldfish retinal ganglion cells' soma size during regeneration

The goldfish optic nerve regenerates after sectioning. Recently both short-term (30 days) and long-term (4 months) recovery of various goldfish behaviors were observed after optic nerve section. Using intracellular injection of Lucifer Yellow (LY) the morphology of regenerating ganglion cells in goldfish retina after optic nerve section over a 4 month period have been investigated. In normal retinas, most cells (96-98%) were 7-10 mu m in soma diameter which increased with increasing distance from the optic disc. Only two or three short, thin processes could be traced with LY. The remaining cells (2-4%) were 13-16 mu m in soma diameter and all of the long dendritic trees could be traced with LY. The most conspicuous morphological change observed was cellular hypertrophy, which occurred for 20-90 days after axotomy. Neuronal processes were also hypertrophic in this period. The percentage increase in hypertrophy of the central ganglion cells tended to be slightly higher compared to cells from other regions. These morphological changes peaked at 60 days after axotomy and Fully disappeared by 120 days after axotomy. The slow recovery of ganglion cells' soma size may reflect the slow return to the normal number of optic axon terminals in the tectum during regeneration. (C) 2000 Elsevier Science Ireland Ltd and the Japan Neuroscience Society. All rights reserved.