Static-Magnetic-Fields of Dental Magnets Influence Calcium Channels of Trigeminal-Ganglion-Neurons

OBJECTIVES: To study the effects of static-magnetic-fields (SMF) produced by permanent dental magnets on the electrophysiological properties of calcium channels on trigeminal-ganglion-neurons (TRGNs). METHODS: Acutely dissociated TRGNs of neonatal SD rats were exposed to 125mT and 12.5mT SMF in exposure devices which were made to simulating the fields of commonly used dental magnets. Whole-cell patch-clamp recordings and laser scanning confocal microscopy were carried out to observe the changes of voltage-gated calcium channels (VGCCs) currents and intracellular free Ca2+ concentration in TRGNs, respectively. RESULTS: (1) No changes of activation kinetics of VGCCs currents were found when TRGNs were exposed to 125mT and 12.5mT SMF. However, the inactivation rate and velocity were significantly altered by 125mT SMF. (2) The fluctuation of intracellular free Ca2+ concentration within TRGNs were slowed by 125mT and 12.5mT SMF. When the devices were removed, the Ca2+ concentration level showed partial recovery in the TRGNs previously exposed by 125mT SMF, while there was a full recovery found in the 12.5mT SMF exposed neurons. CONCLUSIONS: Those experimental findings suggested that the moderate-intensity SMF of dental magnets had certain effects on the electrophysiological characteristics of ion channel on cellular level. Such influences might be intensity-dependent and were not permanent. The mechanism underlying those changes was believed to be related to the magnetic reorientation of membrane phospholipids caused by moderate-intensity SMF through diamagnetic anisotropy effects.