Effects of repeated electroconvulsive seizures on spontaneous alternation behavior and locomotor activity in rats

Epileptic patients are at a significantly higher risk for impairments of cognitive function and behavioral abnormalities. In this study, we investigated the effect of repeated electroconvulsive shock (ECS)-induced seizures on the spontaneous alternation behavior in a Y-maze test and the locomotor activity in an open-field test, and examined the effects of anti-epileptic drugs in rats. ECS was administered for seven consecutive days and the Y-maze and open-field tests were performed 24 h after the last ECS administration. The repeated electroconvulsive seizures significantly impaired the spontaneous alternation and increased the locomotor activity. Moreover, these behavioral changes induced by the seven administrations of ECS persisted for at least 28 d. The inhibition of the ECS-induced seizures through the daily pretreatment of the phenytoin (120 mg/kg, intraperitoneally (i.p.)), phenobarbital (60 mg/kg, i.p.) and valproate (400 mg/kg, i.p.) abolished the locomotor hyperactivity in the open-field test. The impaired spontaneous alternation behavior in the Y-maze test was also significantly suppressed by the treatment with phenytoin and valproate. However, phenobarbital injection produced no significant ameliorating effect in the Y-maze test. These results suggest that the inhibition of ECS-induced seizures through phenytoin and valproate injections suppress the development of impairment of spontaneous alternation and the locomotor hyperactivity.