50 Hz magnetic fields of varying flux intensity affect cell shape changes in invertebrate immunocytes: The role of potassium ion channels

Abstract

The effect induced by exposure to 50 Hz magnetic fields (MFs) in immunocytes from the mussel Mytilus galloprovincialis is evaluated. The whole animal was exposed for 15 and 30 min to MF intensities ranging from 200 to 1,000 microT. The changes in the cellular shape of immunocytes, expressed as shape factor (SF), were studied at different times after addition of the chemotacting substance N-formyl-Meth-Leu-Phe (fMLP). Results show that MFs provoke differing delays in fMLP-induced cellular shape changes: 200 microT are ineffective, while levels from 300 microT upwards cause a significant increase in immunocyte SF values compared to controls. Reactivation of the cells is possible up to an intensity of 600 microT. The use of PCO 400, an opener of ATP-sensitive K+ channels, shows that potassium channels are involved in the effect of MFs on M. galloprovincialis immunocytes.

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

“…In conclusion, the present investigation of fMLPinduced cellular shape changes in immunocytes from M. galloprovincialis exposed to 50 Hz MFs justifies the conclusion that both calcium and potassium [Ottaviani et al, 2002] channels are fundamental for the system. Both respond to the various MF flux intensities in the same manner, and the response is time independent.…”

“…As expected [Ottaviani et al, 2002], immunocytes collected from animals exposed to MFs at intensities of 300 and 400 mT showed delayed cell adhesion and the addition of fMLP resulted in a less marked cell activation (Table 3).…”

“…As previously reported [Ottaviani et al, 2002], fMLP activated the immunocytes of M. galloprovincialis, and the computer evaluations of the immunocyte shape changes, expressed as shape factor (SF), showed values that differed significantly from those observed in the controls (Table 1). As stated in the Materials and Methods section, the SF was evaluated every 5 min from 0 to 20 min.…”

“…This may indicate either a possible enhanced fragility of the cells provoked by MFs, allowing easier Ca 2þ flux across the plasma membrane or better utilization of the available Ca 2þ to counteract cell death. As observed in a previous study on potassium channels [Ottaviani et al, 2002], the MF damage to Ca 2þ channels induced by short exposure to MF at appropriate intensities is not permanent.…”

Effects of 50 Hz sinusoidal magnetic fields on Hsp27, Hsp70, Hsp90 expression in porcine aortic endothelial cells (PAEC)

“…Moreover, previous experiments [Ottaviani et al, 2002;Gobba et al, 2003] reported an influence of 50 Hz MF, in the same range of intensity used in this study, onto Ca 2þ and K þ ion channels. This may suggest that Ca 2þ and K þ channels might be the primary target for the MF action, and this may lead to the activation of Na þ /K þ ATPase in order to restore ion homeostasis, with consequent ATP consumption, but this hypothesis requires further investigation.…”