Synergic convulsant effects of dihydrofolic and kainic acid after intracaudate infusion in rats.

In rats the microinjection of kainic acid into the caudate nucleus produced dose-dependent motor and ECoG discharges. Similarly dihydrofolic acid microinfused into the same area produced an intense pattern of stereotyped movements, circling and high voltage electrocortical spikes, sharp waves and other abnormalities similar is those occurring in human epilepsy. The administration of dihydrofolic acid into the same site 10 min after kainic acid significantly increased the percentage of rats showing epileptic motor and ECoG seizures and potentiated the severity and duration of these effects. In conclusion, the present experiments provide evidence for the potentiation of the neurotoxic effects of folic and kainic acid when given in association into the brain.