[Transcranial magnetic stimulation versus electroconvulsive shocks: neuroanatomical investigations in rats]

Since the time of introducing ECT to the clinical practice, the method always raised questions regarding possibility that the current running through structures of a brain may evoke structural changes and, as a result, evoke convulsive attacks. Pathological changes (swelling, gliosis, atrophy, necrosis) were observed most often after "mega"--schemes including series of several to several hundred ECT treatments. Regime used nowadays including only 8-12 ECT sessions seems to be entirely safe. There are, however, only a few experimental works dealing with this problem. In 1992 research started on a new neurophysiological technique--transcranial magnetic stimulation (TMS) in depression. The advantage of this method is that is does not seem to evoke convulsive attacks. Prolonged rapid rate TMS (rTMS) seems to be particularly efficient in treatment of depression. Despite thousands of works describing various functional effects of TMS, there are obviously no researches on structural effects of the technique. In the case of experimental research on animals a few works were published and their results seem to be ambiguous. We have examined the influence of prolonged repetitive rTMS (B = 1.4 T, t = 5.5 min, f = 30 Hz), and standard ECT (I = 150 mA, t = 0.5 s, f = 50 Hz) on the structure of brain tissue in rats. Both groups of animals (n = 10) received 12 stimulation sessions. After the treatment the animals were routinely processed for electron microscopy (EM) and for light microscopy (LM). Our investigations suggest that the technique of ECT shows a considerable neurotoxic potential. In comparison to ECT--the rTMS method seems to be more safe.