Effects of electromagnetic fields on membrane ion transport of cultured cells

We have studied the mechanisms of ion transport mediated by Na+/K+-pump and Na+, K+, Cl--cotransport pathway of HeLa cells using Rb+ as an analog for K+, and proposed models of binding of ions for the transport pathways. Also, we clarified the relation between ion and water movements in the cells. Based on these findings, we have studied the effects of homogeneous and time-varying magnetic fields on the ion transport activity. The research presented here covers (i) brief explanations of our kinetic studies on the ion transport pathways for promoting understanding of the effects of magnetic fields on the pathways, (ii) our and other reports of the effects of magnetic fields on ion transport systems

Effects of electromagnetic fields on membrane ion transport of cultured cells

We have studied the mechanisms of ion transport mediated by Na+/K+-pump and Na+, K+, Cl--cotransport pathway of HeLa cells using Rb+ as an analog for K+, and proposed models of binding of ions for the transport pathways. Also, we clarified the relation between ion and water movements in the cells. Based on these findings, we have studied the effects of homogeneous and time-varying magnetic fields on the ion transport activity. The research presented here covers (i) brief explanations of our kinetic studies on the ion transport pathways for promoting understanding of the effects of magnetic fields on the pathways, (ii) our and other reports of the effects of magnetic fields on ion transport systems

Effect of exposure to an extremely low frequency- electromagnetic field on the cellular collagen with respect to signaling pathways in osteoblast-like cells

The effect of exposure to extremely low frequency-electromagnetic field (ELFEMF : 3 mT, 60 Hz) on differentiation of mouse osteoblast-like MC3T3-E1 cells was examined together with addition of insulin-like growth factor I (IGF-I). As a marker of the differentiation, the cellular collagen content was determined by the absorbance of Sirius red-stained cells measured at the wavelength of 510-520 nm with an imaging microspectroscopy. Exposure to ELF-EMF increased significantly the collagen in the cells. Treatment with PD98059, an inhibitor of extracellular signal-regulated kinase 1/2 (ERK1/2) activation, reduced the collagen in all of the cells examined on control, IGF-I addition and ELFEMF exposure, however, PD98059 did not prevent the increase in the collagen caused by ELF-EMF exposure, and IGF-I also increased the collagen in the presence of the inhibitor. When phosphatidylinositol 3-kinase (PI3K) pathway was inhibited by LY294002, the increase in collagen induced by ELF-EMF exposure was accelerated, however, the increase in collagen observed by IGF-I addition was suppressed. Treatment with SB203580, an inhibitor of p38 mitogen-activated protein kinase (p38 MAPK), suppressed the increase in the collagen induced by ELF-EMF exposure, whereas IGF-I addition increased the collagen in the presence of the inhibitor. These results suggested that collagen synthesis stimulated by ELF-EMF exposure was carried out by the participation of p38 MAPK pathway, and that PI3K pathway may have the role to suppress the collagen synthesis induced by ELF-EMF exposure, and that the suppression of the PI3K pathway may allow the acceleration of the collagen synthesis

Effects of a 1.5 T time-varying magnetic field on cell volume regulation of bovine adrenal chromaffin cells in hyposmotic media

Effects of a time-varying magnetic field on cell volume regulation by hyposmotic stress in cultured bovine adrenal chromaffin cells were examined. Through regulatory volume decrease (RVD), cell volume of chromaffin cells that were incubated in a hypotonic medium initially increased, reached a peak and finally recovered to the initial value. Two hour exposure to a magnetic field and addition of cytochalasin D increased peak value and delayed return to initial value. Intracellular F-actin contents initially decreased but returned to normal levels after 10 sec. Two hour exposure to the magnetic field and addition of cytochalasin D continuously reduced the F-actin content. Results suggest that exposure to the magnetic field stimulated disruption of the actin cytoskeleton and that the disruption delayed the recovery to the volume prior to osmotic stress