Effect of pulse magnetic field stimulation on calcium channel current

This study aimed to investigate the effect of low frequency and high amplitude pulse magnetic field (PMF) on Calcium ion channel current of cells. Measurements were done on the Human Embryonic Kidney 293 cells (HEK 293), which have only Calcium ion channels functioning. The whole cell current was measured by patch clamp method, with the clamped voltage ramping from −90 mV to +50 mV across the cell membrane. A PMF was generated by a 400-turn coil connected to a pulse current generator. The frequency of the pulse was 7 Hz, the width of the pulse was 3 ms, and the amplitude of the pulse, or the flux density, was ranging from 6 to 25 mT. The results showed that the profile of the whole cell Calcium channel current could be modified by the PMF. With the PMF applied, the phase shifting occurred: the onset of the channel opening took place several mili-seconds earlier than that without the PWF and correspondingly, the whole cell current reached its maximum earlier, and the current returned back to zero earlier as well. When the PWF was stopped, these effects persisted for a period of time, and then the current profile “recovered” to its original appearance. The decrease of the onset time and peak current time could be due to the local electric potential induced by the PWF and the direct interaction between PMF and ion channels/ions. The exact mechanisms of the observed effects of PMF on the cell are still unknown and need to be further studied.