The retina as a biochemical model of central nervous system regeneration.

The visual system of primitive vertebrates has long served as a useful model for the resynthesis of damaged neurons. The prior optic nerve crush imparts a marked tendency on the part of cultured retinal explants to extend neurites. Neurites grown in culture from retinal ganglion cells of the explant have been characterized by lectin-binding and immunohistochemical techniques. Biochemical studies on the retina following optic nerve crush reveal altered RNA and protein metabolism. Results indicate that tubulin mRNA is activated and that new tubulin synthesis is enhanced following the crush. An early and dramatic increase in the rate of nucleotide phosphokinase activity is also seen. The retinal tissue culture data, together with in vivo studies in normal and newly regrown nerve give additional insight into the nature of the regenerative process.