The effects of weak extremely low frequency magnetic fields on calcium/calmodulin interactions

Abstract

Mechanisms by which weak electromagnetic fields may affect biological systems are of current interest because of their potential health effects. Lednev has proposed an ion parametric resonance hypothesis (Lednev, 1991, Bioelectromagnetics, 12:71-75), which predicts that when the ac, frequency of a combined dc-ac magnetic field equals the cyclotron frequency of calcium, the affinity of calcium for calcium-binding proteins such as calmodulin will be markedly affected. The present study evaluated Lednev's theory using two independent systems, each sensitive to changes in the affinity of calcium for calmodulin. One of the systems used was the calcium/calmodulin-dependent activation of myosin light chain kinase, a system similar to that previously used by Lednev. The other system monitored optical changes in the binding of a fluorescent peptide to the calcium/calmodulin complex. Each system was exposed to a 20.9 microT static field superimposed on a 20.9 microT sinusoidal field over a narrow frequency range centered at 16 Hz, the cyclotron frequency of the unhydrated calcium ion. In contrast to Lednev's predictions, no significant effect of combined dc-ac magnetic fields on calcium/calmodulin interactions was indicated in either experimental system.

Calmodulin‐dependent cyclic nucleotide phosphodiesterase activity is altered by 20 μT magnetostatic fields

“…This interpretation of the data bears on the two reports [Hendee et al, 1996;Coulton et al, 2000] that failed to find any weak magnetic field effect on Ca 2þ /CaM/MLCK activity. In both instances, there was no consideration given to studying the extended range of calcium concentrations that we found necessary.…”

Biphasic effects of static magnetic fields on cutaneous microcirculation in rabbits

“…Therefore, it is important to investigate the effects of SMF on these enzymes that could transduce the calcium signal and effect short-term biological responses. Nevertheless, when fluorescence experiments were used to determine the effects of SMF on Ca 2ϩ -dependent interactions of calmodulin with the fluorescent calmodulin-binding domain peptide, no effects of SMF were seen between 0 and 200 T [Hendee et al, 1996].…”

Factors confounding cytosolic calcium measurements in Jurkat E6.1 cells during exposure to ELF magnetic fields

“…Others have reported a decrease in cytosolic calcium or calcium signalling on exposure to ELF MF [Conti et al, 1985;Yost and Liburdy, 1992;Galvanovskis et al, 1999]. There is an almost equal amount of literature reporting no effects of ELF MF [Garcia-Sancho et al, 1994;Hendee et al, 1996;Lyle et al, 1997].…”