Chlorinated hydrocarbon pesticides and amygdaloid kindling

Previous studies by our laboratory have shown that exposures to either lindane or dieldrin enhanced the rate of acquisition of the fully kindled amygdaloid seizure in the rat. To examine whether this enhancement generalizes to all groups of chlorinated hydrocarbon pesticides, the effect of dichlorodiphenyltrichloroethane (DDT) or chlordecone (kepone) was examined on the acquisition rate of the kindled amygdaloid seizure in the rat. Daily DDT exposure (5, 10 or 20 mg/kg, PO) failed to modify the rate of acquisition of the kindled amygdaloid seizure despite resulting in tremors in many of the rats in the high dose group. A single high dose of kepone (50 mg/kg) which resulted in up to 9 days of tremors and weight loss in the treated animals, also failed to modify the rate of kindling acquisition. These data demonstrate that not all CNS active chlorinated hydrocarbon pesticide exposures result in enhancement of kindling acquisition. The kindled amygdaloid seizure model of epilepsy appears to differentiate between the neurotoxic consequences of chlorinated hydrocarbon pesticides that cause myoclonus and seizures (e.g., lindane and dieldrin) and those that primarily cause tremors (DDT and kepone).