Abstract
Mouse submaxillary nerve growth factor (NGF) increases the length and density of neurites extended from embryonic chick ciliary ganglia in vitro. The effect is not as pronounced as with dorsal root ganglia, but it occurs at the same low concentrations of NGF. This effect was observed on polyornithine substrata with or without pretreatment of the substratum with conditioned medium. NGF did not significantly increase the length or density of neurites extended from spinal cord or neural retina explants in the same culture conditions. Stimulation of ciliary ganglion neurite outgrowth did not occur when NGF was replaced with cytochrome c or epidermal growth factor, whereas insulin had an effect comparable to that of NGF when present at much higher concentrations. Four different purified preparations of NGF gave identical results. The purity of two of these preparations was determined after radioiodination; greater than 98% of the radioactivity migrated as a single band on polyacrylamide gels, and greater than 94% of the radioactivity was bound by affinity purified anti-NGF antibody. The effect of NGF on neurite growth could be separated from its effect on neuronal survival. NGF failed to promote the survival of ciliary ganglion neurites even at concentrations 1000-fold higher than those which significantly stimulated neurite growth.(ABSTRACT TRUNCATED AT 250 WORDS)