Effects of magnetic fields on many functions of human and other mammalian cells and proposal of guidelines and Standard for Human Health

1. 随时间变化的1.5 T磁场不影响Ca^<2+>跨质膜内流，但强烈抑制Ca^<2+>从添加多种神经递质诱导的细胞内Ca^<2+>库释放。Ca^<2+>储存通过ryanodine受体释放的Ca^<2+>也受暴露抑制。暴露于强磁场下，通过添加咖啡因或atp，可强烈抑制嗜铬细胞瘤细胞（PC12细胞）细胞内Ca^<2+>库释放Ca^<2+>。添加神经生长因子（NGF）诱导PC12细胞的神经突生长。在NGF存在的情况下，暴露于极低频（ELF）磁场会刺激分化。利用傅里叶变换红外光谱（FT-IR）研究了极低频磁场对HeLa细胞膜结构的影响。这种曝光使酰胺I波段的吸光度峰向更小的波数移动，降低了酰胺II波段的吸光度峰，并在1600 cm^<-1>附近增加了吸光度。这些结果表明，极低频场暴露对肽键的N-H面内弯曲和C-N拉伸振动具有可逆影响，改变了细胞膜蛋白的α -螺旋和β -片的二级结构。我们发现在ELF场和酸性培养基中培养的细胞在FT-IR光谱上有相似的变化，但这些变化与在高K^+培养基中培养的细胞不同。

1. Exposure to the time-varying 1.5 T magnetic field did not affect Ca^<2+> influx across plasma membrane of bovine adrenal chromaffin cells, but strongly inhibited Ca^<2+> release from intracellular Ca^<2+> stores induced by addition of variety of neurotransmitters. Ca^<2+> release from Ca^<2+> stores via ryanodine receptor also suppressed by the exposure.2. Exposure to the strong magnetic field strongly suppressed Ca^<2+> release from intracellular Ca^<2+> stores of pheochromocytoma cells (PC12 cells) by addition of caffeine or ATP.3. Addition of nerve growth factor (NGF) induced a neurite outgrowth of PC12 cells. In the presence of NGF, exposure to an extremely low frequency (ELF) magnetic field stimulate the differentiation.4. We measured the effects of ELF magnetic field on membrane structure of HeLa cells studied by Fourier transform infrared (FT-IR) spectroscopy. This exposure shifted the peak absorbance of the amide I band to a smaller wave number, reduced the peak absorbance of the amide II band, and increase absorbance at around 1600 cm^<-1>. These results suggest that the ELF field exposure has reversible effects on the N-H inplane bending and C-N stretching vibrations of peptide linkages, the changes the secondary structures of alpha-helix and beta-sheet in cell membrane proteins. We found similar changes in FT-IR spectra between cells exposed to ELF field and those incubated in an acidic medium, but these changes were different from those incubated in an high K^+ medium.