On the relation between seizures and brain lesions after intracerebroventricular kainic acid.

To analyze the relation between kainic acid-induced limbic seizures and the associated brain lesions, various doses of kainic acid (117-940 pmol) were administered intracerebroventricularly to unanesthetized rats. Rats which experienced status epilepticus developed lesions in several limbic, neocortical and thalamic regions. However, rats which experienced only temporally discrete seizures (less than 30 min each) suffered neuronal degeneration exclusively in the CA3-CA4 area ipsilateral to the kainic acid infusion, even when other regions exhibited the same total electrographic seizure duration. These results can best be explained by postulating that, in addition to evoking seizures, kainic acid also enhances the toxic effects of seizures on CA3-CA4 neurons.