REGIONAL INCREASES IN BRAIN-DERIVED NEUROTROPHIC FACTOR AND NERVE GROWTH-FACTOR MESSENGER-RNAS DURING AMYGDALOID KINDLING, BUT NOT IN ACIDIC AND BASIC FIBROBLAST GROWTH-FACTOR MESSENGER-RNAS

We studied mRNA levels for neurotrophic factors using the amygdaloid k indling model of epilepsy. One hour after stage 5 kindled seizures, th ere were four-to fivefold increases in brain-derived neurotrophic fact or (BDNF) mRNA in rat dentate gyrus and perirhinal cortex. Nerve growt h factor (NGF) mRNA levels were increased bilaterally in some (but not all) limbic areas. There were no detectable changes in acidic fibrobl ast GF (aFGF) mRNA or basic fibroblast GF (bFGF) mRNA for 24 h after t he kindled seizures. During kindling, levels of BDNF mRNA in the denta te gyrus correlated with projection to generalized seizures, whereas N GF mRNA in the limbic regions continued to increase during seizure dev elopment. These results indicate that the induction of mRNAs for neuro trophic factors, especially for BDNF mRNA in the dentate gyrus, corres ponds to the increases in metabolic and electrical ictal discharge ass ociated with kindled seizures. The persistent increase observed in NGF mRNA may be related to enhanced synaptic efficacy during kindling, bu t aFGF and bFGF are presumed to have little relation to the kindling p rocess.