[The behavioral effects of the transcranial magnetic brain stimulation in rat: the comparison with electroshock]

The few experimental studies suggest that repetitive rapid-rate transcranial magnetic stimulation (TMS) evokes in the brain functional and structural changes similar to those evoked by electroconvulsive therapy (ECT). The aim of the present work was to compare the influence of the repetitive TMS (B = 1.6 T; f = 20 and 30 Hz; t = 5 and 5.5 minutes; N = 9 and 18 days) and that of ECT (I = 150 mA; f = 50 Hz; t = 0.5 s; N = 9 days) on rats' behaviour in the tests of free field, tail flick, motor hyperactivity after administration of apomorphine and in forced swimming. None of the rats subjected to TMS suffered from convulsive attack, which followed every electroconvulsive shock. In the free field test it was detected that neither TMS nor ECT applied individually or repetitively disturbed general motor activity of rats. Repetitive electroconvulsive shocks caused analgesia, prolonging the latency of tail flick by 46% (p < 0.001). Moreover, the tail flick test revealed hyperalgesia in the rats subjected to TMS (24 and 21% of control values respectively; p = 0.05). Motor hyperactivity of rats stimulated with administration of apomorphine was intensified both by TMS (by 58% at maximum in the 30th minute of the experiment; p = 0.001) and, all the more, by ECT (by 92% at maximum at the end of the test; p = 0.01). In the forced swimming test, the greatest decrease of inertia period was observed ECT--up to 50% of control values (p = 0.001). TMS had weaker effects--the decrease amounted to 29% of control values (p = 0.01). The shortening effect depended on the parameters of TSM. The obtained results seem to confirm that TMS, like ECT, evokes in rats certain reactions suggesting its antidepressive action, but causes less undesirable effects.