Regional increases in brain-derived neurotrophic factor and nerve growth factor mRNAs during amygdaloid kindling, but not in acidic and basist growth factor mRNAs.

We studied mRNA levels for neurotrophic factors using the amygdaloid k indling model of epilepsy. One hour after stage 5 kindled seizures, there were four-to fivefold increases in brain-derived neurotrophic factor (BDNF) mRNA in rat dentate gyrus and perirhinal cortex. Nerve growth factor (NGF) mRNA levels were increased bilaterally in some (but not all) limbic areas. There were no detectable changes in acidic fibroblast GF (aFGF) mRNA or basic fibroblast GF (bFGF) mRNA for 24 h after the kindled seizures. During kindling, levels of BDNF mRNA in the dentate gyrus correlated with projection to generalized seizures, whereas NGF mRNA in the limbic regions continued to increase during seizure development. These results indicate that the induction of mRNAs for neurotrophic factors, especially for BDNF mRNA in the dentate gyrus, corresponds to the increases in metabolic and electrical ictal discharge associated with kindled seizures. The persistent increase observed in NGF mRNA may be related to enhanced synaptic efficacy during kindling, but aFGF and bFGF are presumed to have little relation to the kindling process.