Yost M G, Liburdy R P
School of Public Health, University of California, Berkeley 94720.
FEBS Lett. 1992 Jan 20;296(2):117-22. doi: 10.1016/0014-5793(92)80361-j.
We have tested the hypothesis that extremely low frequency (ELF) time-varying magnetic fields act in combination with static magnetic fields to alter calcium signalling in the lymphocyte. Results indicate that a 60-min exposure of thymic lymphocytes at 37 +/- 0.05 degrees C to a 16 Hz, 421 mG (42.1 microT) magnetic field simultaneously with a colinear static magnetic field of 234 mG (23.4 microT) (a.c./d.c. field intensity ratio = 1.8) inhibits calcium influx triggered by the mitogen Concanavalin A. Significantly, resting lymphocytes do not respond to the fields, thus, only mitogen-activated cells undergoing calcium signalling exhibit a field response. These results indicate that signal transduction involving calcium is an important biological constraint which operates to mediate this field interaction. Additional split field exposures show that the presence of the a.c. field or the d.c. field alone does not produce an effect. This is consistent with a proposed parametric resonance theory of interaction of low intensity magnetic fields with biological systems (L.L. Lednev (1991) Bioelectromagnetics 12, 71-75), which predicts the occurrence of biological effects at specific values for the frequency and field intensity of the ELF and static magnetic fields.
我们已经对极低频（ELF）时变磁场与静磁场共同作用以改变淋巴细胞中钙信号这一假说进行了测试。结果表明，在37±0.05℃下，将胸腺淋巴细胞暴露于16赫兹、421毫高斯（42.1微特斯拉）的磁场中60分钟，同时施加一个234毫高斯（23.4微特斯拉）的共线静磁场（交流/直流场强比 = 1.8），会抑制由促有丝分裂剂伴刀豆球蛋白A触发的钙内流。值得注意的是，静息淋巴细胞对这些磁场无反应，因此，只有正在经历钙信号传导的有丝分裂原激活细胞才表现出对磁场的反应。这些结果表明，涉及钙的信号转导是介导这种磁场相互作用的一个重要生物学限制因素。额外的分场暴露实验表明，单独存在交流场或直流场均不会产生效应。这与所提出的低强度磁场与生物系统相互作用的参数共振理论（L.L. Lednev（1991年），《生物电磁学》12卷，71 - 75页）相一致，该理论预测在极低频和静磁场的特定频率和场强值下会出现生物学效应。
