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

1.时变磁场部分抑制了依赖于Ca~(2+)和Gt~(2+)的K~(++)通道对K~+的吸收。当细胞置于高K^+培养液中时，[Ca^&lt；2+&gt；]c增加到原来的1.4倍左右，但暴露在磁场中完全抑制了这种增加。在高K^+培养液中加入离子霉素使[Ca^&lt；2+&gt；]c增加到对照细胞的水平，与磁场暴露无关。但外加离子霉素不能恢复磁场对K+吸收的抑制作用。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抑制乙酰胆碱、缓激肽、咖啡因、离子霉素和thapsigargin刺激的嗜铬细胞[Ca~(2+)]_c的一过性升高。此外，在1，4，5-三磷酸肌醇负载的细胞中，[Ca~(2+)&t；2+&gt；]c显著升高，这种升高可被暴露所抑制。…抑制缓激肽诱导的[Ca~(2+)]_c升高在磁场外放置1小时后，细胞大部分恢复到0.5小时以上。我们的结果表明，磁场暴露抑制了细胞内钙离子的释放，但不影响缓激肽与细胞膜上缓激肽受体的结合以及1，4，5-三磷酸肌醇的产生。用衰减全反射红外光谱仪研究了50赫兹极低频(ELF)磁场(最大41.7-43.6mT)对活体HeLa细胞膜蛋白结构的影响。暴露1min使酰胺I带的峰值吸光度移动到一个较小的波数，显著降低了酰胺II带的吸光度，并在1600 cm~(-1)~(-1)处增大了吸光度。这些结果表明，暴露在ELF磁场中可逆地影响了多肽键的N-H面内弯曲和C-N伸缩振动，并改变了细胞膜蛋白质中α-螺旋和β-折叠的二级结构。暴露于60赫兹磁场(最大3mT)的极低频磁场进一步增加了由神经生长因子刺激的PC12细胞的分化。较少

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