Epileptiform activity increases the level of nerve growth factor in cerebrospinal fluid of epileptic patients and in hippocampal neurons in tissue culture.

A neurite-stimulating effect was induced by both the cerebrospinal fluid of epileptic patients and the media of co-cultures of rat hippocampus and chick embryo sensory neurons after veratridine treatment. Cerebrospinal fluid from patients with epilepsy stimulated extensive neurite growth in the organotypic culture of chick embryo dorsal root ganglia. The anti-nerve growth factor antibody partly blocked the neurite-stimulating effect of the cerebrospinal fluid. Co-cultures of newborn rat hippocampus and chick embryo dorsal root ganglia were used to investigate the involvement of neurotrophic factors into the processes which are activated by neuronal activity. The data obtained suggest that veratridine, an epileptiform agent, gave rise to an elevation in the level of neurotrophic factors in the culture media and neurite outgrowth of dorsal root ganglia sensory neurons. The anti-nerve growth factor antibody was shown to block the neurite-stimulating effect mediated by veratridine. These results indicate that the epileptiform activity of neurons evokes the expression of neurotrophins.