Effects of Magnetic field on Nerve Transmission and Analyses of Efficiency and Safety for Human on Application of Magnetic Field.

1. 时变磁场（MF）通过Ca^<2+>依赖的K^+通道部分抑制了K^+的摄取。当细胞置于高K^+介质中时，[Ca^<2+>]c增加到原始水平的1.4倍左右，但暴露在磁场中完全抑制了这种增加。将离子霉素添加到高K^+介质中，使[Ca^<2+>]c提高到对照细胞的水平，无论暴露在磁场中如何。但加入离子霉素后，磁场对K^+吸收的抑制作用没有恢复。K^+内流的抑制可能与细胞表面电学性质的改变有关。时变MF可抑制乙酰胆碱、缓激肽、咖啡因、离子霉素和thapsigargin刺激的[Ca^<2+>]c的瞬时升高。此外，[Ca^<2+>]c在肌醇1,4,5-三磷酸负载细胞中显著增加，这种增加被暴露抑制。对缓激素诱导的[Ca^<2+>]c升高的抑制作用，在将细胞置于磁场外1小时后恢复。我们的研究结果表明，暴露于emf可抑制细胞内Ca^<2+>储存的Ca^<2+>释放，但缓激肽与细胞膜缓激肽受体的结合和肌醇1,4,5-三磷酸的产生不受影响。利用衰减全反射红外光谱研究了50 Hz极低频（ELF） MF（最大41.7 ~ 43.6 mT）对HeLa活细胞膜蛋白结构的影响。暴露1 min后，酰胺I波段的吸光度峰向较小的波数偏移，酰胺II波段的吸光度强烈降低，在1600 cm^<-1>附近吸光度增加。这些结果表明，暴露在极低频磁场下可可逆地影响肽键的N-H面内弯曲和C-N拉伸振动，并改变细胞膜蛋白质的α -螺旋和β -片的二级结构。暴露于60 Hz至3 mT的极低频MF下，通过添加神经生长因子刺激PC12细胞的分化进一步增加。少

1. The time-varying magnetic fields (MF) partly suppressed K^+ uptake through Ca^<2+>-dependent K^+ channels. When the cells were placed in the high K^+ medium, [Ca^<2+>]c increased to about 1.4 times the original level, but exposure to the magnetic fields completely suppressed the increase. Addition of ionomycin to the high K^+ medium increased [Ca^<2+>]c to the level of control cells, regardless of exposure to the magnetic field. But the inhibition of K^+ uptake by the magnetic field was not restored by addition of ionomycin. The suppression of K^+ influx could relate to a change in electric properties of cell surface.2. The time-varying MF inhibited the transient increase in [Ca^<2+>]c stimulated by acetylcholine, bradykinin, caffeine, ionomycin and thapsigargin in chromaffin cells. Also, [Ca^<2+>]c was markedly increased in inositol 1,4,5-trisphosphate-loaded cells, and this increase was inhibited by exposure. Inhibition of bradykinin-induced increase in [Ca^<2+>]c by exposure for … More 0.5 hr was mostly recovered after placing the cells for 1 hr outside the magnetic field. Our results indicate that the MF-exposure inhibits Ca^<2+> release from intracellular Ca^<2+> stores, but that bradykinin binding to bradykinin receptors of the cell membrane and inositol 1,4,5-trisphosphate production are not influenced.3. The effects of exposure to 50 Hz extremely-low-frequency (ELF) MF (maximally 41.7-43.6 mT) on structures of membrane protein of living HeLa cells were studied by the attenuated total reflection infrared spectroscopy. The exposure for 1 min shifted the peak absorbance of amide I band to a smaller wave number, strongly reduced the absorbance of amide II band and increased the absorbance at around 1600 cm^<-1>. These results suggest that exposure to the ELF magnetic field reversibly influences N-H inplane bendings and C-N stretching vibrations of peptide linkages, and changes secondary structures of alpha-helix and beta-sheet in proteins of the cell membrane.4. Exposure to ELF MF to 60 Hz MF (maximally 3 mT) further increased the differentiation of PC12 cells stimulated by addition of nerve growth factor. Less