Differential Effect of Swimming Stress and Exercise Models in Pentylenetetrazol Induced Kindling of Rats

Epilepsy is a neurological disorder which is modulated by different situations and activities. Stress and exercise can have effects on epilepsy; it can reduce or increase its occurrence. We investigated the effect of acute and chronic stress and also regular moderate exercise on the epileptogenesis. In this experimental study, 82 male Wistar rats divided into 7 groups including 2 exercised and stressed categories, received 40 mg/kg pentylenetetrazol (PTZ) every 48 h up to 13 injections. Then the convulsive behavior was rated by Racine scale. The acute stress was applied by a 30 min swimming session in the water with temperatures of 20, 25 and 32ºC. The chronic stress was created by repeated sessions of 30 min daily swimming for 5 days in 20ºC water. The exercise was a 60 min swimming daily, 5 days a week and for 8 weeks in 25 and 32ºC. We demonstrated that the acute stress showed a decrease in kindling threshold, except for the stress in 25ºC water which lowered the kindling rate. Similarly, the chronic stress decreased the kindling threshold in the first 5 injections. The exercise did not reduce the kindling threshold but did reduce the kindling rate in both 25 and 32ºC water. It is concluded that the swimming stress enhanced the kindling process, but the swimming exercise prevented the kindling. Therefore, the animal learns to cope with the condition in a repeated regular physical activity.