Expression of <i>c-fos</i> in cortical neuron cultures under dynamic magnetic field is not suppressed by calcium channel blockers

Previously, we developed a dynamic magnetic field (DMF) device using neodymium magnets that induced c-fos expression in cortical neurons, while activity-regulated cytoskeleton-associated protein (Arc), and brain-derived neurotrophic factor (BDNF) remained unaffected. The precise signal transduction pathway for c-fos induction under DMF was unclear. This study aimed to investigate the mechanism of immediate early gene (IEG) induction using calcium channel blockers (CCBs). Six experiments were conducted with cortical neurons, employing an NMDA receptor antagonist and an L-type voltage-dependent calcium channel blocker as CCBs. Neuronal cultures were exposed to DMF, CCBs, or both, and IEG expression (Arc, c-fos, BDNF) was measured through polymerase chain reaction. Results showed a tendency for increased c-fos expression with DMF exposure, which was unaffected by CCBs. In contrast, Arc and BDNF were not induced under DMF exposure but were significantly inhibited by CCBs. These findings suggest that c-fos induction under DMF involves a distinct pathway, potentially relevant to stress resistance and drug discovery.