c-Fos induction in visceral and vestibular nuclei of the rat brain stem bya 9.4 T magnetic field

Recently, it has been shown that rats placed in a 9.4 T static magnetic fie ld for 30 min after drinking a glucose-saccharin solution develop a conditi oned taste aversion (CTA) to glucose-saccharin. We sought to identify brain stem regions that are activated by the 9.4 T magnetic field exposure using c-Fos immunohistochemistry. Rats were restrained in a 9.4 T magnet for 30 min; sham-exposed rats were restrained but not exposed to the magnetic fiel d. The magnetic field induced significantly more c-fos-positive cells than sham treatment in the solitary tract, parabrachial, medial vestibular, prep ositus, and supragenualis nuclei. These results suggest that magnetic field exposure causes neural activation in visceral and vestibular nuclei that m ay promote CTA learning. (C) 2000 Lippincott Williams & Wilkins.