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IMPORTANTE TRABAJO DE REVISIÓN QUE PONE EN EVIDENCIA LOS MECANISMOS DE ACCIÓN SUBYACENTES A LOS EFECTOS DE LOS CAMPOS Y RADIACIONES ELECTROMAGNÉTICAS EN LOS SERES VIVOS. Electromagnetic fields act via activation of voltage-gated calcium channels to produce beneficial or adverse effects
Domingo 28 de julio de 2013 · 1184 lecturas
Electromagnetic fields act via activation of voltage-gated
calcium channels to produce beneficial or adverse effects
Martin L. Pall *
Professor Emeritus of Biochemistry and Basic Medical Sciences, Washington State University, Portland, OR, USA
Received: January 8, 2013; Accepted: May 20, 2013
● Introduction
● Possible modes of action following
voltage-gated calcium channel stimulation
● Therapeutic bone-growth stimulation
via Ca2+/nitric oxide/cGMP/protein kinase G
● Ca2+/nitric oxide/peroxynitrite and
pathophysiological
responses to EMF exposures: the example of
single-strand DNA breaks
● Discussion and conclusions
Abstract
The direct targets of extremely low and microwave frequency range electromagnetic fields (EMFs) in producing non-thermal effects have not
been clearly established. However, studies in the literature, reviewed here, provide substantial support for such direct targets. Twenty-three
studies have shown that voltage-gated calcium channels (VGCCs) produce these and other EMF effects, such that the L-type or other VGCC
blockers block or greatly lower diverse EMF effects. Furthermore, the voltage-gated properties of these channels may provide biophysically
plausible mechanisms for EMF biological effects. Downstream responses of such EMF exposures may be mediated through Ca2+/calmodulin
stimulation of nitric oxide synthesis. Potentially, physiological/therapeutic responses may be largely as a result of nitric oxide-cGMP-protein
kinase G pathway stimulation. A well-studied example of such an apparent therapeutic response, EMF stimulation of bone growth, appears to
work along this pathway. However, pathophysiological responses to EMFs may be as a result of nitric oxide-peroxynitrite-oxidative stress pathway
of action. A single such well-documented example, EMF induction of DNA single-strand breaks in cells, as measured by alkaline comet
assays, is reviewed here. Such single-strand breaks are known to be produced through the action of this pathway. Data on the mechanism of
EMF induction of such breaks are limited; what data are available support this proposed mechanism. Other Ca2+-mediated regulatory changes,
independent of nitric oxide, may also have roles. This article reviews, then, a substantially supported set of targets, VGCCs, whose stimulation
produces non-thermal EMF responses by humans/higher animals with downstream effects involving Ca2+/calmodulin-dependent nitric oxide
increases, which may explain therapeutic and pathophysiological effects.
Keywords: intracellular Ca2+ - voltage-gated calcium channels - low frequency electromagnetic field exposure - nitric
oxide - oxidative stress - calcium channel blockers
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