Acidic fibroblast growth factor enhances neurite outgrowth and stimulates expression of GAP-43 and T alpha 1 alpha-tubulin in cultured neurones from adult rat dorsal root ganglia

The effects of acidic fibroblast growth factor (FGF-1) on neurite outgrowth were investigated and related to the levels of mRNA encoding the growth associated protein genes GAP-43 and the neuron specific alpha-tubulin, T alpha 1, in primary cultures of dorsal root ganglia (DRG) neurones from adult rats. In response to FGF-1, sensory neurones produced a high level of neurite outgrowth which was highest (2.70 +/- 0.09-fold over control) at 50 ng/ml of FGF-1. Treatment with 250 ng/ml of a monoclonal anti-nerve growth factor (NGF) antibody, which can block the similar increase in neurite outgrowth produced by 0.1 ng/ml of NGF, did nor antagonise the response to 50 ng/ml of FGF-1, showing that FGF-1 has effects on regeneration in adult sensory neurones not mediated via NGF. The estimated ED(50) value for FGF-1 was 20 ng/ml for induction of neurite outgrowth. Treatment with FGF-1 elevated the level of mRNA for GAP-43 by 2.9-fold at 50 ng/ml and T alpha 1 alpha-tubulin by 9.2-fold at 10 ng/m, though the FGF-1 concentration/effect range for stimulation of these two mRNA was different from that for neurite outgrowth.