In the present study, we attempted to clarify the controversial question whether basic fibroblast growth factor (bFGF, FGF-2) mRNA is present or absent in the embryonic central nervous system (CNS). For this purpose we analyzed the expression of the FGF-2 mRNA in the embryonic and adult forebrain, brainstem, and spinal cord using the highly specific ribonuclease protection assay. Using this method we were able to detect FGF-2 mRNA in the rat CNS of embryonic day (E) 16 and 17, however, at lower levels compared to adult FGF-2 mRNA levels. In addition, we show that a FGF-2 antisense transcript is expressed in embryonic CNS tissue. Furthermore, using this method, we demonstrate FGF receptor 1 mRNA in the rat embryonic and adult CNS. The presence of FGF-2 and FGF receptor 1 suggests a physiological role for this growth factor during the development of the embryonic CNS.