Magnetic stimulation induces neuronal c-fos via tetrodotoxin-sensitive sodium channels in organotypic cortex brain slices of the rat

Repetitive transcranial magnetic stimulation is a novel non-invasive method with antidepressant properties, where electromagnetic fields are applied v ia an electrode. The aim of the present study was to investigate in an in v itro model if magnetic stimulation may activate the transcription factor c- fos. Organotypic brain slices of the parietal cortex were cultured for 2 we eks and then treated with a magnetic stimulator. Immunohistochemistry was u sed to detect c-fos like immuno reactivity. We show that magnetic stimulati on (1 Hz, 10 min, 75% machine output/magstim 200 rapid stimulator) transien tly enhanced c-fos 3-6 h after stimulation. Co-localization experiments rev ealed that c-fos was expressed in neurons but not astroglia. The activation of c-fos by magnetic stimulation was inhibited by the sodium-channel block er tetrodotoxin (TTX) (10 muM). It is concluded that magnetic stimulation i nduces neuronal c-fos via TTX-sensitive sodium channels in organotypic cort ex slices. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.