We evaluated the role of nitric oxide and lipid peroxidation in the pathophysiological mechanisms of seizures in genetically epilepsy prone (GEP) rats and DBA/2 mice with genetically determined audiogenic epilepsy. In rats and mice acoustic stimulation led to locomotor activation followed by clonic-tonic seizures. The contents of nitric oxide and lipid peroxidation products at the peak of seizures markedly surpassed the control level.