Effects of 50 Hz magnetic fields on fMLP-induced shape changes in invertebrate immunocytes: The role of calcium ion channels

Plasma membrane Ca(2+) channels in immunocytes from the mussel Mytilus galloprovincialis exposed to 50 Hz sine wave magnetic fields (MFs) of various strengths were studied. At levels of 300 microT and above, MFs reduce shape changes in immunocytes induced by the chemotactic substance N-formyl-Meth-Leu-Phe, and this effect involves L-type Ca(2+) channels. Upon the addition of the Ca(2+) blocker verapamil to molluscan immunocytes exposed to MFs results in a synergistic cytotoxic action, while in the presence of the Ca(2+) opener SDZ-202, 791, a reactivation of the cells is observed. This suggests that, as previously reported for potassium channels, the damage to Ca(2+) channels induced by short exposure to MF at appropriate intensities is not permanent.