Neurite outgrowth from explanted Xenopus retina: an effect of prior optic nerve section.

Experimental conditions are described for the in vitro study of explanted eyes from embryos of Xenopus laevis and of retinas from older larvae. When eyes are explanted from embryos of stages 25-34, a rapid outgrowth of fibroblast-like and pigment cells is observed, upon which a neuritic outgrowth is eventually superimposed. Outgrowth from the retina of later stage tadpoles (50-54) is not seen until about a week following explantation and resembles the mixed cell outgrowth observed in whole eye explants from early stage embryos. If, however, the optic nerve of an older tadpole is cut 7 days prior to explantation, a purely neuritic outgrowth is seen from the previously denervated retina within 1-3 days.