Diazepam induces FGF-2 mRNA in the hippocampus and striatum

We have examined the possibility that the gamma -aminobutyric acid (GABA) s ystem can influence the expression of basic fibroblast growth factor (FGF-2 ) in select regions of the brain. The GABA agonist diazepam was systemicall y injected in adult rats, and the expression of FGF-2 was examined between 6 h and 7 days post-injection. Results of nuclease protection assays showed significant increases in FGF-2 mRNA in the hippocampus and striatum, but n ot in the caudal cerebral cortical region-starting by 6 h following diazepa m injection and returning to approximately control values by 24 h. In situ hybridization showed elevated FGF-2 mRNA labeling in the hippocampal format ion, mostly in the pyramidal layer of the CA1 and CA2 subfields and in the dentate gyrus hilar region. These results indicate that diazepam treatment up-regulates FGF-2 expression in select regions of the brain and suggest th at GABA may promote neuroplasticity in concert with FGF-2. (C) 2000 Elsevie r Science Inc.