Power-frequency electromagnetic fields and the capacitative calcium entry system in SV40-transformed Swiss 3T3 cells

The present study was designed to test the hypothesis that a 60 Hz electrom agnetic field could affect the influx of calcium ions across the plasma mem brane through the so-called capacitative calcium entry system. Recordings o f cytosolic calcium-ion concentrations in SV40-transformed Swiss 3T3 cells were obtained in real time during exposure to magnetic fields ranging from 0.3-50 mT or to sham conditions using the calcium-sensitive photoprotein ae quorin, This was done for cell populations whose capacitative entry system was activated by either bradykinin or thapsigargin under a variety of exper imental conditions. No effects of the magnetic field were observed on brady kinin-induced calcium transients and, with the exception of a small but sta tistically significant increase observed in experiments performed at 50 mT, no effects of the fields were observed on baseline calcium levels prior to or after such transients. The magnetic fields also had no effects on the s ize or kinetics of any of the thapsigargin-induced calcium transients. Over all, the data fail to support the hypothesis tested in this work. (C) 2000 by Radiation Research society.