Immunocytochemical demonstration of fibroblast growth factor in cultured chick and rat neurons

The presence of fibroblast growth factor (FGF) was investigated by immunocytochemistry in cultured neuronal cells derived from the peripheral (PNS) and the central nervous system (CNS) of chick and rat embryos. Polyclonal antimouse FGF antibodies, which cross-react with basic and acidic FGF, were used in the peroxidase immunocytochemical staining method. FGF immunoreactivity was found in neurons. Staining intensity in chick and rat brain neuronal cells increased during the culture period, reached a maximum after 6-8 days, and subsequently declined. Embryonic chick ciliary and dorsal root ganglionic (DRG) neurons as well as DRG neurons from newborn rat displayed intense FGF immunoreactivity at 12 and 48 hr in culture. Nonneuronal cells were not stained. The data demonstrate for the first time that cultured neurons from the CNS and PNS contain FGF.