Effects of Electromagnetic Fields On K+(Rb+) Uptake by HeLa Cells

Miyamoto, Hiroshi; Yamaguchi, Hisao; Ikehara, Toshitaka; Kinouchi, Y.

doi:10.1007/978-0-585-31661-1_7

Cited by 9 publications

(7 citation statements)

References 24 publications

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“…Rb C is used in place of K C in the cellular experiment. Exposure to strong homogeneous magnetic fields with various magnetic flux densities of less than 1.6 T had no significant effect on either active or passive Rb C influxes into HeLa cells [10]. The patch-clamp method was used to measure transmembrane Na C and K C currents in SH-Sy5Y neuroblastoma cells exposed to static magnetic fields of 0.1, 0.5, and 7.5 mT [11].…”

Section: Ion Transportmentioning

confidence: 99%

The review of cellular effects of a static magnetic field

Miyakoshi

2006

Science and Technology of Advanced Materials

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The effects of static magnetic fields at the cellular level are reviewed. Past studies have shown that a static magnetic field alone does not have a lethal effect on the basic properties of cell growth and survival under normal culture conditions, regardless of its magnetic density. It has also been shown that cell cycle distribution is not influenced by extremely strong static magnetic fields (up to a maximum of 10 tesla (T)). A further area of interest is whether static magnetic fields cause DNA damage, which can be evaluated by determination of the frequency of micronucleus formation. The presence or absence of such micronuclei can confirm whether a particular treatment damages cellular DNA. This method has been used to confirm that a static magnetic field alone has no such effect. However, the frequency of micronucleus formation changes significantly when certain treatments (for example, X-irradiation and mitomycin C) are given during exposure to a strong static magnetic field. It has also been reported that treatment with trace amounts of ferrous ions in the cell culture medium and exposure to a static magnetic field increases DNA damage, which is detected using the comet assay. Several reports suggest that a strong static magnetic field may affect the ion transport and the gene expression. In addition, many studies have found a strong magnetic field can induce orientation phenomena in cell culture. q

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Section: Ion Transportmentioning

confidence: 99%

The review of cellular effects of a static magnetic field

Miyakoshi

2006

Science and Technology of Advanced Materials

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“…We have previously reported that micro¯uorometric examinations of cells loaded with the¯uorescent pH indicator 4-heptadecyl-7-hydroxycoumarin and membrane potential indicator diS-C3-(5) suggest an increase in the negative charge on the cell surface during exposure to the time-varying magnetic ®eld . This change possibly occurs by eddy currents induced by the time-varying magnetic ®eld, rather than a direct effect of the magnetic ®eld itself [Miyamoto et al, 1996]. We have recently obtained data showing that ELF magnetic ®elds (80 mT, 50 Hz) in¯uence membrane protein structure of HeLa cells, as assessed by Fourier transform infrared spectroscopy (unpublished data).…”

Section: Discussionmentioning

confidence: 95%

“…This change possibly occurs by eddy currents induced by the time-varying magnetic ®eld, rather than a direct effect of the magnetic ®eld itself [Miyamoto et al, 1996]. We have recently obtained data showing that ELF magnetic ®elds (80 mT, 50 Hz) in¯uence membrane protein structure of HeLa cells, as assessed by Fourier transform infrared spectroscopy (unpublished data).…”

Section: Discussionmentioning

confidence: 96%

“…We previously reported the effects of electromagnetic ®elds on membrane ion transport [Miyamoto et al, 1996]. In the previous report, we measured the effects of time-varying magnetic ®elds on Rb (K ) in¯ux into HeLa cells incubated in a normal medium.…”

Section: Discussionmentioning

confidence: 99%

“…These studies elucidate changes in the ion transport activity and electric properties of the cell membrane when exposed to magnetic or electromagnetic ®elds. Taking these results into consideration, we tested the effect on ouabain-sensitive K uptake of HeLa cells by intermittent exposures at an interval of 3 s (1/6 Hz) to a strong electromagnetic ®eld of quasi-rectangular form, whose¯ux density changed between 70 mT and nearly 2 T, and found signi®cant reversible inhibition of Napump activity Miyamoto et al, 1996]. We suggested that the inhibitory effect would relate to a change in electrical properties of the cell membrane caused by eddy currents induced by the time-varying magnetic ®eld.…”

Section: Introductionmentioning

confidence: 99%

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Effects on Rb+(K+) uptake of HeLa cells in a high K+ medium of exposure to a switched 1.7 tesla magnetic field

Ikehara¹,

Park²,

Yamaguchi³

et al. 2000

Bioelectromagnetics

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Effects of a switched, time‐varying 1.7 T magnetic field on Rb+(K+) uptake by HeLa S3 cells incubated in an isosmotic high K+ medium were examined. The magnetic flux density was varied intermittently from 0.07–1.7 T at an interval of 3 s. K+ uptake was activated by replacement of normal medium by high K+ medium. A membrane‐permeable Ca2+ chelating agent (BAPTA‐AM) and Ca2+‐de pendent K+ channel inhibitors (quinine, charibdotoxin, and iberiotoxin) were found to reduce the Rb+(K+ ) uptake by about 30–40%. Uptake of K+ that is sensitive to these drugs is possibly mediated by Ca2+‐dependent K+ channels. The intermittent magnetic field partly suppress ed the drug‐sensitive K+ uptake by about 30–40% (P < 0.05). To test the mechanism of inhibition by the magnetic fields, intracellular Ca2+ concentration ([Ca2+]c) was measured using Fura 2‐AM. When cells were placed in the high K+ ; medium, [Ca2+]c increased to about 1.4 times the original level, but exposure to the magnetic fields completely suppressed the increase (P < 0.01). Addition of a Ca2+ ionophore (ionomycin) to the high K+ medium increased [Ca2+]c to the level of control cells, regardless of exposure to the magnetic field. But the inhibition of K+ uptake by the magnetic fields was not restored by addition of ionomycin. Based on our previous results on magnetic field‐induced changes in properties of the cell membrane, these results indicate that exposure to the magnetic fields partly suppresses K+ influx, which may be mediated by Ca2+‐dependent K+ channels. The suppress ion of K+ fluxes could relate to a change in electric properties of cell surface and an inhibition of Ca2+ influx mediated by Ca2+ channels of either the cell plasma membrane or the inner vesicular membrane of intracellular Ca2+ stores. Bioelectromagnetics 21:228–237, 2000. © 2000 Wiley‐Liss, Inc.

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Effects of static magnetic fields on nicotinic cholinergic receptor function

Tolosa

Bouzat

Cravero

2011

Bioelectromagnetics

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Ligand-gated ion channel kinetics were studied in mammalian transfected cells encoding adult mouse muscle acetylcholine (ACh) receptors. We measured macroscopic and single-channel currents using the outside-out and cell-attached patch-clamp configurations. Cultured cells were exposed to moderate intensity inhomogeneous static magnetic fields up to 180 mT and measurements were performed for temperatures ranging from 5 to 50 °C. We found no significant changes in ACh-elicited macroscopic or single-channel currents. We observed the expected dependence in current decay constants with temperature, but negligible magnetic field influence on the channel's kinetics.

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Effects of Electromagnetic Fields On K+(Rb+) Uptake by HeLa Cells

Cited by 9 publications

References 24 publications

The review of cellular effects of a static magnetic field

The review of cellular effects of a static magnetic field

Effects on Rb+(K+) uptake of HeLa cells in a high K+ medium of exposure to a switched 1.7 tesla magnetic field

Effects of static magnetic fields on nicotinic cholinergic receptor function

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