Neuroendocrine and behavioral effects of repetitive transcranial magnetic stimulation in a psychopathological animal model are suggestive of antidepressant-like effects

The neuroendocrine and behavioral effects of repetitive transcranial magnet ic stimulation (rTMS) were investigated in two rat lines selectively bred f or high and low anxiety-related behavior. The stimulation parameters were a djusted according to the results of accurate computer-assisted and magnetic resonance imaging-based reconstructions of the current density distributio ns induced by rTMS in the rat and human brain, ensuring comparable stimulat ion patterns in both cases. Adult male rates were treated in two 3-day seri es under halothane anesthesia. In the forced swim test, rTMS-treatment indu ced a more active coping strategy in the high anxiety-related behavior rats only (time spent struggling; 332% vs. controls), allowing these animals to reach the performance of low anxiety-related behavior rats. In contrast, r TMS-treated low anxiety-related behavior rats did not change their swimming behavior. The development of active coping strategies in high anxiety-rela ted behavior rats was accompanied by a significantly attenuated stress-indu ced elevation of plasma corticotropin and corticosterone concentrations. In summary, the behavioral and neuroendocrine effects of rTMS of frontal brai n regions in high anxiety-related behavior rats are comparable to the effec ts of antidepressant drug treatment. Interestingly, in the psychopathologic al animal model repetitive transcranial magnetic stimulation induced change s in stress coping abilities in the high-anxiety line only. (C) 2001 Americ an College of Neuropsychopharmcology. Published by Elsevier Science Inc.