Effect of repetitive transcranial magnetic stimulation on forced swimming test

Repetitive transcranial magnetic stimulation (rTMS) and electroconvulsive shock (ECS) have been shown to affect mood in health and disease. Evidence to date has demonstrated an antidepressant potential for rTMS and electroconvulsive therapy (ECT). The present experiment, aimed at comparing the effects of ECS and rTMS in rats, employed one test used for screening of antidepressant activity: the forced swimming test (FST). In this study, the authors investigated whether chronic rTMS influenced active behavior in the rat FST, similar to ECS. Male Wistar rats received rTMS treatment daily, for 10 days as is commonly used for ECT treatment. Control rats received sham treatment by placing the stimulation coil in a perpendicular position to the rat's head. Passing a current through earclip electrodes for 1 s induced ECS. The control animals were treated identically, but current was not applied. The FST was carried out 24 h after the last rTMS or ECS. The immobility time in the FST was not significantly affected by rTMS and ECS for 1 day. The immobility time in the FST was significantly shortened at rTMS and ECS for 10 days. Chronic treatment with rTMS, similar to chronic treatment with ECS, decreased the immobility time in the FST. These results indicate that chronic treatment with rTMS might have antidepressant effect similar to chronic treatment with ECS.