Mossy fiber lesion reduces the probability that kainic acid will provoke CA3 hippocampal pyramidal cell bursting.

Hippocampal slices prepared from rats which had received a mossy fiber lesion differed in their response to 50 nM kainic acid. Those slices in which the mossy fiber projection had been substantially destroyed were significantly less likely to develop epileptiform bursting in area CA3 than slices in which the mossy fiber projection was only modestly damaged. Similarly, mossy fiber lesions prevent the development of electrographic status epilepticus after intracerebroventricular administration of kainic acid in 26% of rats. Therefore mossy fiber lesions probably act, both in vivo and in vitro, by reducing the sensitivity of CA3 hippocampal pyramidal cells to the epileptogenic action of kainic acid.