Alternating phases of FGF receptor and NGF receptor expression in the developing chicken nervous system.

Patterns of expression of transcripts encoding receptors for fibroblast growth factor and nerve growth factor (FGF-R and NGF-R) in the developing chick nervous system are compared using in situ hybridization histochemistry. FGF-R transcripts are expressed abundantly in the germinal neuroepithelial layer. Expression ceases as cells migrate into the mantle layer and returns during late maturation of neuronal populations, including cholinergic nuclei of the basal forebrain, brainstem reticular and motor nuclei, and cerebellar Purkinje and granule neurons. The pattern of NGF-R expression is generally reciprocal to that of FGF-R in the CNS and in some phases of development of the PNS. These results suggest that FGF and NGF may act sequentially rather than in concert during neuronal development.