A study of the action of valproic acid on the kindling effect.

The effect of an antiepileptic drug, valproic acid (VPA), on an experimental form of epilepsy, the kindling phenomenon, is described. In cat, 50 mg/kg i.p. per day is sufficient to block the progressive establishment of generalized seizures produced normally by repetitive electrical stimulation of the amygdala. However, a focal afterdischarge persists during the entire treatment. Higher doses (75-150 mg/kg) are necessary to protect the animal against the generalized tonic-clonic seizure when the kindling phenomenon is established. These effects and the action of barbiturates, which was also tested, seem to attribute to VPA a complex role in the mechanism of this action.