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Liu L, Huang B, Lu Y, Zhao Y, Tang X, Shi Y. Interactions between electromagnetic radiation and biological systems. iScience 2024; 27:109201. [PMID: 38433903 PMCID: PMC10906530 DOI: 10.1016/j.isci.2024.109201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024] Open
Abstract
Even though the bioeffects of electromagnetic radiation (EMR) have been extensively investigated during the past several decades, our understandings of the bioeffects of EMR and the mechanisms of the interactions between the biological systems and the EMRs are still far from satisfactory. In this article, we introduce and summarize the consensus, controversy, limitations, and unsolved issues. The published works have investigated the EMR effects on different biological systems including humans, animals, cells, and biochemical reactions. Alternative methodologies also include dielectric spectroscopy, detection of bioelectromagnetic emissions, and theoretical predictions. In many studies, the thermal effects of the EMR are not properly controlled or considered. The frequency of the EMR investigated is limited to the commonly used bands, particularly the frequencies of the power line and the wireless communications; far fewer studies were performed for other EMR frequencies. In addition, the bioeffects of the complex EM environment were rarely discussed. In summary, our understanding of the bioeffects of the EMR is quite restrictive and further investigations are needed to answer the unsolved questions.
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Affiliation(s)
- Lingyu Liu
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bing Huang
- Brain Function and Disease Laboratory, Department of Pharmacology, Shantou University Medical College, 22 Xin-Ling Road, Shantou 515041, China
| | - Yingxian Lu
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yanyu Zhao
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Xiaping Tang
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Westlake Laboratory of Life Sciences and Biomedicine, Xihu District, Hangzhou 310024, Zhejiang Province, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University; Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
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Geesink JH, Meijer DKF. Bio-soliton model that predicts non-thermal electromagnetic frequency bands, that either stabilize or destabilize living cells. Electromagn Biol Med 2018; 36:357-378. [PMID: 29164985 DOI: 10.1080/15368378.2017.1389752] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Solitons, as self-reinforcing solitary waves, interact with complex biological phenomena such as cellular self-organization. A soliton model is able to describe a spectrum of electromagnetism modalities that can be applied to understand the physical principles of biological effects in living cells, as caused by endogenous and exogenous electromagnetic fields and is compatible with quantum coherence. A bio-soliton model is proposed, that enables to predict which eigen-frequencies of non-thermal electromagnetic waves are life-sustaining and which are, in contrast, detrimental for living cells. The particular effects are exerted by a range of electromagnetic wave eigen-frequencies of one-tenth of a Hertz till Peta Hertz that show a pattern of 12 bands, and can be positioned on an acoustic reference frequency scale. The model was substantiated by a meta-analysis of 240 published articles of biological electromagnetic experiments, in which a spectrum of non-thermal electromagnetic waves were exposed to living cells and intact organisms. These data support the concept of coherent quantized electromagnetic states in living organisms and the theories of Fröhlich, Davydov and Pang. It is envisioned that a rational control of shape by soliton-waves and related to a morphogenetic field and parametric resonance provides positional information and cues to regulate organism-wide systems properties like anatomy, control of reproduction and repair.
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Affiliation(s)
- J H Geesink
- a Department of biophysics , Groningen , The Netherlands
| | - D K F Meijer
- a Department of biophysics , Groningen , The Netherlands
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El-Gohary OA, Said MAA. Effect of electromagnetic waves from mobile phone on immune status of male rats: possible protective role of vitamin D. Can J Physiol Pharmacol 2017; 95:151-156. [DOI: 10.1139/cjpp-2016-0218] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There are considerable public concerns about the relationship between mobile phone radiation and human health. The present study assesses the effect of electromagnetic field (EMF) emitted from a mobile phone on the immune system in rats and the possible protective role of vitamin D. Rats were randomly divided into six groups: Group I: control group; Group II: received vitamin D (1000 IU/kg/day) orally; Group III: exposed to EMF 1 h/day; Group IV: exposed to EMF 2 h/day; Group V: exposed to EMF 1 h/day and received vitamin D (1000 IU/kg/day); Group VI: exposed to EMF 2 h/day and received vitamin D (1000 IU/kg/day). After 30 days of exposure time, 1 h/day EMF exposure resulted in significant decrease in immunoglobulin levels (IgA, IgE, IgM, and IgG); total leukocyte, lymphocyte, eosinophil and basophil counts; and a significant increase in neutrophil and monocyte counts. These changes were more increased in the group exposed to 2 h/day EMF. Vitamin D supplementation in EMF-exposed rats reversed these results when compared with EMF-exposed groups. In contrast, 7, 14, and 21 days of EMF exposure produced nonsignificant differences in these parameters among all experimental groups. We concluded that exposure to mobile phone radiation compromises the immune system of rats, and vitamin D appears to have a protective effect.
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Affiliation(s)
- Ola Ahmed El-Gohary
- Department of Medical Physiology, Faculty of Medicine, Benha University, Benha, Qalubia, Egypt
- Department of Medical Physiology, Faculty of Medicine, Benha University, Benha, Qalubia, Egypt
| | - Mona Abdel-Azeem Said
- Department of Medical Physiology, Faculty of Medicine, Benha University, Benha, Qalubia, Egypt
- Department of Medical Physiology, Faculty of Medicine, Benha University, Benha, Qalubia, Egypt
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Golbach LA, Philippi JG, Cuppen JJ, Savelkoul HF, Verburg-van Kemenade BL. Calcium signalling in human neutrophil cell lines is not affected by low-frequency electromagnetic fields. Bioelectromagnetics 2015; 36:430-43. [DOI: 10.1002/bem.21924] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 05/11/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Lieke A. Golbach
- Cell Biology and Immunology Group; Wageningen University; The Netherlands
| | - John G.M. Philippi
- Lab of Biophysics and Wageningen NMR Centre; Wageningen University; The Netherlands
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Extremely low frequency electromagnetic field exposure does not modulate toll-like receptor signaling in human peripheral blood mononuclear cells. Cytokine 2011; 54:43-50. [DOI: 10.1016/j.cyto.2010.12.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 11/08/2010] [Accepted: 12/18/2010] [Indexed: 01/23/2023]
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Mostafa RM, Moustafa YM, Ali FM, Shafik A. SEX HORMONE STATUS IN MALE RATS AFTER EXPOSURE TO 50 HZ, 5 MTESLA MAGNETIC FIELD. ACTA ACUST UNITED AC 2009; 52:363-9. [PMID: 16873136 DOI: 10.1080/01485010600667092] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The question of whether extremely low frequency magnetic fields can affect biological system has attracted attention. The theoretical possibility of such an interaction is often questioned and the site of interaction is unknown. The influence of extremely low frequency magnetic field of 50 Hz, 5 mTesla on sex hormone status was studied. 60 male albino rats were divided into 6 groups and were continuously exposed to 50 Hz, 5 mTesla magnetic field generated by magnetic field chamber for periods of 1, 2 and 4 weeks. For each experimental point, sham treated group was used as a control. Assay of serum testosterone LH, FSH, and prolactin were performed. Serum testosterone showed no significant changes. FSH showed significant increase than sham exposed group after 1 week magnetic field exposure. LH showed significant increase than sham exposed group only after 4 weeks magnetic field exposure, while serum prolactin hormone level showed a significant increase in all magnetic field exposed groups than sham exposed animals. Exposure to 50 Hz, 5 mTesla magnetic field for periods of 1, 2 and 4 weeks has no effect on testosterone level, some changes on FSH and LH serum levels and increase in serum prolactin level.
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Affiliation(s)
- R M Mostafa
- Department of Basic Sciences, College of Medicine, Sharjah University, Sharjah, UAE
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Maaroufi K, Had-Aissouni L, Melon C, Sakly M, Abdelmelek H, Poucet B, Save E. Effects of prolonged iron overload and low frequency electromagnetic exposure on spatial learning and memory in the young rat. Neurobiol Learn Mem 2009; 92:345-55. [PMID: 19394433 DOI: 10.1016/j.nlm.2009.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 04/09/2009] [Accepted: 04/16/2009] [Indexed: 11/30/2022]
Abstract
Low-frequency electromagnetic fields (EMF) have been suggested to affect the brain via alterations of blood-brain barrier permeability to iron. Because of an immature blood-brain barrier, the young brain may be particularly vulnerable to EMF exposure. It is therefore possible that behavioral and neurotoxic effects resulting from EMF-induced iron excess in the brain would be greater in young adults. The objective of the present study was to investigate the interaction between low-frequency EMF and iron overload in young rats. In Experiment 1, we tested the effects of iron overload on spatial learning and memory. Iron treatment did not affect performance in a reference (Morris water maze) and a working memory task (8-arm radial maze). In contrast, detection of a spatial change in an object exploration task was impaired. These effects correlated with modifications of the serotoninergic metabolism. In Experiment 2, the combination of EMF exposure and iron overload was tested. As in Experiment 1, rats were not impaired in reference and working memory tasks but were mildly impaired in the detection of the spatial change. Overall, the results showed an effect of iron overload on spontaneous spatial memory processes. However, low-frequency EMF exposure did not potentiate the effects of iron overload in young rats.
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Affiliation(s)
- Karima Maaroufi
- Laboratory of Neurobiology and Cognition, UMR 6155 Aix-Marseille Université CNRS, Marseille, France
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Aktas I, Akgun K, Cakmak B. Therapeutic effect of pulsed electromagnetic field in conservative treatment of subacromial impingement syndrome. Clin Rheumatol 2006; 26:1234-9. [PMID: 17086382 DOI: 10.1007/s10067-006-0464-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Revised: 10/05/2006] [Accepted: 10/05/2006] [Indexed: 10/24/2022]
Abstract
Subacromial impingement syndrome (SIS) is a frequent cause of shoulder pain. Our purpose in this double-blinded, randomized, and controlled study was to demonstrate whether the pulsed electromagnetic field (PEMF) provides additional benefit when used with other conservative treatment modalities in acute phase rehabilitation program of SIS. Forty-six patients with unilateral shoulder pain who had been diagnosed as having SIS were included in this trial. The cases were randomly separated into two groups. All cases received a treatment program for 3 weeks consisting of Codman's pendulum exercises and subsequent cold pack gel application on shoulders with pain 5 times a day, restriction of daily activities that require the hands to be used over the head, and meloxicam tablet 15 mg daily. One group was given PEMF; the other group was given sham PEMF daily, 25 min per session, 5 days per week for 3 weeks. Shoulder pain during rest and activity and which causes disturbance of sleep was evaluated using a visual analogue scale, and total Constant score investigated shoulder function. Daily living activities were evaluated by shoulder disability questionnaire. Results were assessed before and after treatment. When compared with the baseline values, significant improvements in all these variables were observed at the end of the treatment in both groups (p<0.05). No significant difference between treatments was observed for any of these variables (p>0.05). There is no convincing evidence that electromagnetic therapy is of additional benefit in acute phase rehabilitation program of SIS.
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Affiliation(s)
- Ilknur Aktas
- Department of Physical Medicine and Rehabilitation, Saygi Hospital, Cerrahpasa Medical Faculty, Istanbul University, Turkey.
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Markov MS. Myosin Light Chain Phosphorylation Modification Depending on Magnetic Fields. I. Theoretical. Electromagn Biol Med 2004. [DOI: 10.1081/jbc-200026319] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Liboff AR, Cherng S, Jenrow KA, Bull A. Calmodulin-dependent cyclic nucleotide phosphodiesterase activity is altered by 20 microT magnetostatic fields. Bioelectromagnetics 2003; 24:32-8. [PMID: 12483663 DOI: 10.1002/bem.10063] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Absorbance measurements at 660 nm of calmodulin (CaM) dependent cyclic nucleotide phosphodiesterase activity under cell free conditions indicate that 30-min exposures to weak magnetostatic field intensities alters this activity, compared to zero magnetic field exposures. This effect depends nonlinearly on the concentration of free calcium, with maximum magnetic interaction apparently occurring at an optimal Ca(2+) concentration corresponding to 50% activation (EC(50)). If one regards Ca(2+)/CaM activation as a switching process, then increasing the magnetic field at Ca(2+) levels in excess of optimal acts to bias this switch towards lower calcium concentrations. A magnetic dependence has been previously reported by others in an homologous system, CaM dependent myosin light chain phosphorylation, implying that there may be an underlying magnetic interaction that involves the initial Ca(2+)/CaM binding process common to both enzymatic pathways. The level of magnetostatic intensity at which this effect is observed ( approximately 20 microT) implies that CaM activation may be functionally sensitive to the geomagnetic field.
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Affiliation(s)
- A R Liboff
- Department of Physics, Oakland University, Oakland, Michigan 48309, USA.
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Ikehara T, Park KH, Yamaguchi H, Hosokawa K, Houchi H, Azuma M, Minakuchi K, Kashimoto H, Kitamura M, Kinouchi Y, Yoshizaki K, Miyamoto H. Effects of a time varying strong magnetic field on release of cytosolic free Ca2+ from intracellular stores in cultured bovine adrenal chromaffin cells. Bioelectromagnetics 2002; 23:505-15. [PMID: 12224054 DOI: 10.1002/bem.10043] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This study was made to explain the mechanisms for the effects of exposure to a time varying 1.51 T magnetic field on the intracellular Ca(2+) signaling pathway. The exposure inhibited an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) in bovine chromaffin cells induced by addition of bradykinin (BK) to a Ca(2+) free medium. The exposure did not change BK induced production of inositol 1,4,5-trisphosphate (IP(3)). [Ca(2+)](i) was markedly increased in IP(3) loaded cells, and this increase was inhibited by the magnetic field exposure. A similar increase in [Ca(2+)](i) by other drugs, which stimulated Ca(2+) release from intracellular Ca(2+) stores, was again inhibited by the same exposure. However, transmembrane Ca(2+) fluxes caused in the presence of thapsigargin were not inhibited by the magnetic field exposure in a Ca(2+) containing medium. Inhibition of the BK induced increase in [Ca(2+)](i) by the exposure for 30 min was mostly recovered 1 h after exposure ended. Our results reveal that the magnetic field exposure inhibits Ca(2+) release from intracellular Ca(2+) stores, but that BK bindings to BK receptors of the cell membrane and intracellular inositol IP(3) production are not influenced.
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Affiliation(s)
- Toshitaka Ikehara
- Department of Physiology, School of Medicine, The University of Tokushima, Kuramoto-cho, Tokushima 770-8503, Japan
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Mostafa RM, Mostafa YM, Ennaceur A. Effects of exposure to extremely low-frequency magnetic field of 2 G intensity on memory and corticosterone level in rats. Physiol Behav 2002; 76:589-95. [PMID: 12126997 DOI: 10.1016/s0031-9384(02)00730-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
In the present study, we examined the effects of chronic exposure (1 and 2 weeks) to an extremely low-frequency magnetic field (ELFMF) of 2 G intensity on memory in rats using an object recognition task. Comparable groups of rats were exposed for 1, 2 or 4 weeks to ELFMF and the following day blood samples were collected from each rat for the measurement of corticosterone level. Our results demonstrate that exposure to ELFMF induces a significant increase in the level of corticosterone in blood plasma and is associated with impairment in discrimination between familiar and novel objects.
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Affiliation(s)
- Randa M Mostafa
- Zagazig University, Banha School of Medicine, Department of Physiology, Banha, Egypt
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McCreary CR, Thomas AW, Prato FS. Factors confounding cytosolic calcium measurements in Jurkat E6.1 cells during exposure to ELF magnetic fields. Bioelectromagnetics 2002; 23:315-28. [PMID: 11948612 DOI: 10.1002/bem.10019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Reported changes in the cytosolic calcium concentration ([Ca2+](c)) as a result of exposure to extremely low frequency (ELF) magnetic fields (MF) have been equivocal. In this study, we examine the possibility that some of these differences are attributable to variability associated with the cell cycle, pH of the suspension medium, and response to a calcium agonist. We used a custom designed spectrofluorimeter to measure [Ca2+](c) in Indo 1-AM loaded Jurkat E6.1 cells suspended in conditioned RPMI 1640 medium containing 10% fetal bovine serum. Four exposures were examined: zero static MF (Null), 60 Hz 100 microT(peak) sinusoidal MF (AC), 78 microT static MF (DC), and the combination of the 60 Hz and the 78 microT static MF (AD + DC). A significant decrease in normalized [Ca2+](c) values between 375-495 s for the DC and AC + DC groups was found in comparison to the Null group. However, statistical analysis indicated that cell cycle and quality of the alpha-CD3 monoclonal antibody response were significant covariates, while pH was not a significant covariate. When the effect of these covariates was taken into account, all exposure groups were significantly different from the control. Our results suggest that ELF MF effects may not be seen unless correction is made for biological variability of each cell preparation with respect to cell cycle and [Ca2+](c) response to antigen stimulation.
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Affiliation(s)
- Cheryl R McCreary
- Imaging Division Lawson, Health Research Institute, London, Ontario, Canada.
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Abstract
The biphasic effects of locally applied static magnetic fields (SMF) on the cutaneous microcirculation within a rabbit ear chamber (REC) were evaluated under conscious conditions. The microcirculatory vasomotion within a REC was measured continuously and analyzed multilaterally by microphotoelectric plethysmography, a real-time image analyzer and an image shearing monitor. SMF intensities at the REC were controlled at 1 mT and the duration of exposure was 10 min. Seventy-eight experimental trials were carried out on 22 healthy adult rabbits weighing 2.6-3.5 kg. Five experimental groups were chosen at random: 1) no pharmacological treatment or SMF exposure, 2) increased vascular tone induced by noradrenaline infusion without SMF exposure, 3) increased vascular tone induced by noradrenaline infusion with SMF exposure, 4) decreased vascular tone induced by acetylcholine infusion without SMF exposure, 5) decreased vascular tone induced by acetylcholine infusion with SMF exposure. The results demonstrated that SMF significantly enhanced vasodilatation, with increased vasomotion under noradrenaline-induced high vascular tone as well as vasoconstriction with reduced vasomotion under acetylcholine-induced low vascular tone. This suggests, therefore, that SMF can modulate vascular tone due to biphasic modification of vasomotion in the cutaneous tissue.
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Affiliation(s)
- H Okano
- Department of Physiological Hygiene, National Institute of Public Health, Tokyo, Japan
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Ikehara T, Park KH, Yamaguchi H, Hosokawa K, Yoshizaki K, Miyamoto H, Aizawa K, Kinouchi Y. Effects on Rb(+)(K+) uptake of HeLa cells in a high K(+) medium of exposure to a switched 1.7 Tesla magnetic field. Bioelectromagnetics 2000; 21:228-37. [PMID: 10723022 DOI: 10.1002/(sici)1521-186x(200004)21:3<228::aid-bem9>3.0.co;2-i] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
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 Ca(2+) chelating agent (BAPTA-AM) and Ca(2+)-dependent 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 Ca(2+)-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 Ca(2+) concentration ([Ca(2+)]c) was measured using Fura 2-AM. When cells were placed in the high K(+) medium, [Ca(2+)]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 Ca(2+) ionophore (ionomycin) to the high K(+) medium increased [Ca(2+)]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 Ca(2+)-dependent K(+) channels. The suppress ion of K(+) fluxes could relate to a change in electric properties of cell surface and an inhibition of Ca(2+) influx mediated by Ca(2+) channels of either the cell plasma membrane or the inner vesicular membrane of intracellular Ca(2+) stores.
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Affiliation(s)
- T Ikehara
- Department of Physiology, School of Medicine, The University of Tokushima, Tokushima, Japan
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Coulton LA, Barker AT, Van Lierop JE, Walsh MP. The effect of static magnetic fields on the rate of calcium/calmodulin-dependent phosphorylation of myosin light chain. Bioelectromagnetics 2000; 21:189-96. [PMID: 10723019 DOI: 10.1002/(sici)1521-186x(200004)21:3<189::aid-bem6>3.0.co;2-l] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study reports an attempt to confirm a published and well-defined biological effect of magnetic fields. The biological model investigated was the phosphorylation of myosin light chain in a cell free system. The rate of phosphorylation has been reported to be affected in an approximately linear manner by static magnetic field strengths in the range 0-200 microT. We performed three series of experiments, two to test the general hypothesis and a third that was a direct replication of published work. We found no effect of static magnetic field strength on the rate of phosphorylation. Hence, we were unable to confirm that weak static magnetic fields affect the binding of calcium to calmodulin. In view of the difficulty we and other authors have had making independent verifications of claimed biological effects of magnetic fields, we would urge caution in the interpretation of published data until they have been independently confirmed. There are still few well defined biological effects of low level magnetic fields that have been successfully transferred to an independent laboratory.
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Affiliation(s)
- L A Coulton
- Department of Surgical & Anaesthetic Sciences, University of Sheffield, UK.
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Popescu IR, Willows AO. Sources of magnetic sensory input to identified neurons active during crawling in the marine mollusc Tritonia diomedea. J Exp Biol 1999; 202:3029-3036. [PMID: 10518484 DOI: 10.1242/jeb.202.21.3029] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although the nudibranch mollusc Tritonia diomedea orients to the geomagnetic field, the anatomical site and the mechanism of the geomagnetic transducer are not known. Previous work on semi-intact preparations of Tritonia diomedea in which the brain is intact and nerve connections to the periphery are maintained showed that identifiable pedal ganglion neurons Pd5 fired an increased number of action potentials when the horizontal component of the ambient magnetic field was rotated. This response disappeared when all nerves emerging from the brain were cut, suggesting a peripheral locus for the geomagnetic transducer. In the present work, we recorded intracellularly from Pd5 in preparations in which all peripheral nerves were cut except those containing the axons of neurons Pd5 (pedal nerves 2 and 3). These uncut, mixed, sensory-motor trunks innervate the locomotory epithelium of the foot upon which the animal crawls. In this further-reduced preparation, Pd5 again responded to magnetic field rotations with action potentials. To determine the direction of this action potential transmission in response to magnetic field rotations, we analyzed extracellular recordings from nerves containing the Pd5 axons and found that action potentials elicited in Pd5 by magnetic stimuli originate centrally and are transmitted peripherally. In addition, we have explored the behavioral function of Pd5 neurons by simultaneously recording intracellular electrical activity and crawling rate of the semi-intact animal. A significant correlation was found between crawling rate and Pd5 action potential rate. We also found that action potentials in dorsal swim interneurons depolarized both Pd5 and the established locomotion motoneuron Pd21.
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Affiliation(s)
- IR Popescu
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA.
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Abstract
Electrification in developed countries has progressively increased the mean level of extremely low-frequency electromagnetic fields (ELF-EMFs) to which populations are exposed; these humanmade fields are substantially above the naturally occurring ambient electric and magnetic fields of approximately 10(-4) Vm(-1) and approximately 10(-13) T, respectively. Several epidemiological studies have concluded that ELF-EMFs may be linked to an increased risk of cancer, particularly childhood leukemia. These observations have been reinforced by cellular studies reporting EMF-induced effects on biological systems, most notably on the activity of components of the pathways that regulate cell proliferation. However, the limited number of attempts to directly replicate these experimental findings have been almost uniformly unsuccessful, and no EMF-induced biological response has yet been replicated in independent laboratories. Many of the most well-defined effects have come from gene expression studies; several attempts have been made recently to repeat these key findings. This review analyses these studies and summarizes other reports of major cellular responses to EMFs and the published attempts at replication. The opening sections discuss quantitative aspects of exposure to EMFs and the incidence of cancers that have been correlated with such fields. The concluding section considers the problems that confront research in this area and suggests feasible strategies.
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Affiliation(s)
- A Lacy-Hulbert
- Department of Biochemistry, University of Cambridge, England.
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