1
|
Kumar S, Dey S, Jain S. Extremely low-frequency electromagnetic fields: A possible non-invasive therapeutic tool for spinal cord injury rehabilitation. Electromagn Biol Med 2016; 36:88-101. [PMID: 27399648 DOI: 10.1080/15368378.2016.1194290] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Traumatic insults to the spinal cord induce both immediate mechanical damage and subsequent tissue degeneration. The latter involves a range of events namely cellular disturbance, homeostatic imbalance, ionic and neurotransmitters derangement that ultimately result in loss of sensorimotor functions. The targets for improving function after spinal cord injury (SCI) are mainly directed toward limiting these secondary injury events. Extremely low-frequency electromagnetic field (ELF-EMF) is a possible non-invasive therapeutic intervention for SCI rehabilitation which has the potential to constrain the secondary injury-induced events. In the present review, we discuss the effects of ELF-EMF on experimental and clinical SCI as well as on biological system.
Collapse
Affiliation(s)
- Suneel Kumar
- a Department of Physiology , All India Institute of Medical Sciences , New Delhi , India.,b W. M. Keck Center for Collaborative Neuroscience, Rutgers, The State University of New Jersey , Piscataway , NJ , USA
| | - Soumil Dey
- a Department of Physiology , All India Institute of Medical Sciences , New Delhi , India
| | - Suman Jain
- a Department of Physiology , All India Institute of Medical Sciences , New Delhi , India
| |
Collapse
|
2
|
Das S, Kumar S, Jain S, Avelev VD, Mathur R. Exposure to ELF- magnetic field promotes restoration of sensori-motor functions in adult rats with hemisection of thoracic spinal cord. Electromagn Biol Med 2013; 31:180-94. [PMID: 22897399 DOI: 10.3109/15368378.2012.695706] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Clinically effective modalities of treatment for spinal cord injury (SCI) still remain unsatisfactory and are largely invasive in nature. There are reports of accelerated regeneration in injured peripheral nerves by extremely low-frequency pulsed electromagnetic field (ELF-EMF) in the rat. In the present study, the effect of (50 Hz), low-intensity (17.96 μT) magnetic field (MF) exposure of rats after-hemisection of T13 spinal cord (hSCI) was investigated on sensori-motor and locomotor functions. Rats were divided into hSCI (sham-exposed) and hSCI+MF (MF: 2 h/d X 6 weeks) groups. Besides their general conditions, locomotor function by Basso, Beattie, and Brenahan (BBB) score; motor responses to noxious stimuli by threshold of tail flick (TTF), simple vocalization (TSV), tail flick latency (TFL), and neuronal excitability by H-reflex were noted. It is found that, in the hSCI+MF group, a statistically significant improvement over the hSCI control group was noted in BBB score from post-SCI wk2 and TFL and TTF by post-hSCI wk1 and wk3, respectively. Correspondingly, TSV gradually restored by post-hSCI wk5.The threshold of H-reflex was reduced on ipsilateral side vs. contralateral side in hSCI and hSCI+MF group. A complete bladder control was dramatically restored on post-hSCI day4 (vs. day7 of hSCI group) and the survival rate was 100% in the hSCI+MF group (vs. 90% of hSCI group). The results of our study suggest that extremely low-frequency (50 Hz), low-intensity (17.96 μT) MF exposure for 2 h/d x 6wks promotes recovery of sensori-motor behavior including locomotion and bladder control both in terms of temporal pattern and magnitude in hemisection injury of (T13) spinal cord rats.
Collapse
Affiliation(s)
- Suman Das
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | | | | | | | | |
Collapse
|
3
|
Role of the Opioid System in the Modulation of Thermonociceptive Sensitivity of Mollusks Affected by Weak Electromagnetic Factors. NEUROPHYSIOLOGY+ 2012. [DOI: 10.1007/s11062-012-9234-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
4
|
Abstract
There are thousands of experiments in the world of science, but we do not have a uniform system, in which different results from the divergent development of science, as well as from our entire world can be connected to each other in a wholistic way. If divergence predominated over convergence, it would favor destructive and self-disastrous processes. Besides, it is indisputable that such a complex theory must involve the matter of consciousness and of the subconscious, as well as laws of physics, similarly to the concept presented here. According to Neumann's reasoning, and because the brain does not use the language of mathematics, any complex theory should think in terms of tendencies and processes instead of formulas. Therefore, the complex theory described in this paper works in processes. In the first part of this article a possible role of the brain's biopiezoelectric crystals is shown as they could take part in the process of storage of conscious information in a holographic way in the brain. The second part describes a concept of quantum vacuum theory of the unconscious implicit background (subconscious) and its connection with consciousness. In the third part, the global role of virtual particles (scalar waves) in the processes of the brain and in the material world is raised.
Collapse
Affiliation(s)
- ISTVÁN BÓKKON
- National Institute of Chemical Safety, Láng Endre u. 68, Budapest 1238, Hungary
| |
Collapse
|
5
|
Del Seppia C, Mencacci R, Luschi P, Varanini M, Ghione S. Differential magnetic field effects on heart rate and nociception in anosmic pigeons. Bioelectromagnetics 2011; 33:309-19. [PMID: 21953246 DOI: 10.1002/bem.20708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 09/01/2011] [Indexed: 11/09/2022]
Abstract
Several studies have shown that exposure to altered magnetic fields affects nociception by suppressing stress-induced hypoalgesia, and that this effect is reduced or abolished if the treatment is performed in the absence of light. This raises the question as to whether other sources of sensory stimuli may also modulate these magnetic effects. We investigated the possible role of olfaction in the magnetically induced effects on sensitivity to nociceptive stimuli and heart rate (HR) in restraint-stressed homing pigeons exposed to an Earth-strength, irregularly varying (<1 Hz) magnetic field. The magnetic treatment decreased the nociceptive threshold in normally smelling birds and an opposite effect was observed in birds made anosmic by nostril plugging. Conversely, no differential effect of olfactory deprivation was observed on HR, which was reduced by the magnetic treatment both in smelling and anosmic pigeons. The findings highlight an important role of olfactory environmental information in the mediation of magnetic effects on nociception, although the data cannot be interpreted unambiguously because of the lack of an additional control group of olfactory-deprived, non-magnetically exposed pigeons. The differential effects on a pigeon's sensitivity to nociceptive stimulus and HR additionally indicate that the magnetic stimuli affect nociception and the cardiovascular system in different ways.
Collapse
Affiliation(s)
- Cristina Del Seppia
- Institute of Clinical Physiology, National Council of Research, Pisa, Italy.
| | | | | | | | | |
Collapse
|
6
|
Nikolskaya KA, Yeshchenko OV, Pratusevich V. The Opioid System and Magnetic Field Perception. ACTA ACUST UNITED AC 2009. [DOI: 10.3109/15368379909022584] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
7
|
Rakesh RM, Mathur R. Threshold of Pain in Chronic Magnetic Field- (50 Hz, 17.9 μT) Exposed Rats: Effect of Sucrose Ingestion. Electromagn Biol Med 2009; 27:254-65. [DOI: 10.1080/15368370802304130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
8
|
Del Seppia C, Ghione S, Luschi P, Ossenkopp KP, Choleris E, Kavaliers M. Pain perception and electromagnetic fields. Neurosci Biobehav Rev 2007; 31:619-42. [PMID: 17374395 DOI: 10.1016/j.neubiorev.2007.01.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2006] [Revised: 01/17/2007] [Accepted: 01/18/2007] [Indexed: 11/22/2022]
Abstract
A substantial body of evidence has accumulated showing that exposure to electromagnetic fields (EMFs) affects pain sensitivity (nociception) and pain inhibition (analgesia). Consistent inhibitory effects of acute exposures to various EMFs on analgesia have been demonstrated in most studies. This renders examinations of changes in the expression of analgesia and nociception a particularly valuable means of addressing the biological effects of and mechanisms underlying the actions of EMFs. Here we provide an overview of the effects of various EMFs on nociceptive sensitivity and analgesia, with particular emphasis on opioid-mediated responses. We also describe the analgesic effects of particular specific EMFs, the effects of repeated exposures to EMFs and magnetic shielding, along with the dependence of EMF effects on lighting conditions. We further consider some of the underlying cellular and biophysical mechanisms along with the clinical implications of these effects of various EMFs.
Collapse
Affiliation(s)
- Cristina Del Seppia
- Institute of Clinical Physiology, National Council of Research, Pisa, Italy.
| | | | | | | | | | | |
Collapse
|
9
|
Del Seppia C, Mezzasalma L, Messerotti M, Cordelli A, Ghione S. Simulation of the geomagnetic field experienced by the International Space Station in its revolution around the Earth: effects on psychophysiological responses to affective picture viewing. Neurosci Lett 2006; 400:197-202. [PMID: 16529860 DOI: 10.1016/j.neulet.2006.02.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 02/10/2006] [Accepted: 02/17/2006] [Indexed: 11/28/2022]
Abstract
There is evidence suggesting that exposure to an abnormal magnetic environment may produce psychophysiological effects related to abnormalities in responses to stress. This may be of relevance for space medicine where astronauts are exposed to a magnetic field different from that exerted by the Earth. Aim of this study was to assess how the exposure of the head to a magnetic field simulating the one encountered by the International Space Station (ISS) during a single orbit (90 min) around the Earth affects the cardiovascular and psychophysiological parameters. Twenty-four human volunteers were studied double blindly in random order under sham and magnetic exposure. During exposure, the persons were shown a set of pictures of different emotional content while subjective self-rating, skin conductance (SC), blood pressure (BP), and heart rate (HR) were measured. In addition, BP, HR, and tooth pain threshold were assessed before and after exposure. While subjects were under magnetic exposure, skin conductance was strongly differentiated (F(2,36)=22.927; p=0.0001), being high during emotionally involving (positive and negative) pictures and low during neutral pictures. Conversely, when subjects were under sham exposure, no significant differences were observed. There was, however, a trend for higher heart rate during picture viewing under magnetic exposure as compared to sham exposure. No effects were found for the other variables. These results suggest that an abnormal magnetic field that simulates the one encountered by ISS orbiting around the Earth may enhance autonomic response to emotional stimuli.
Collapse
Affiliation(s)
- Cristina Del Seppia
- Institute of Clinical Physiology, National Council of Research (CNR), Via Moruzzi 1, 56124 Pisa, Italy.
| | | | | | | | | |
Collapse
|
10
|
Ghione S, Seppia CD, Mezzasalma L, Bonfiglio L. Effects of 50Hz electromagnetic fields on electroencephalographic alpha activity, dental pain threshold and cardiovascular parameters in humans. Neurosci Lett 2005; 382:112-7. [PMID: 15911132 DOI: 10.1016/j.neulet.2005.02.072] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Revised: 02/25/2005] [Accepted: 02/25/2005] [Indexed: 10/25/2022]
Abstract
Recent studies indicate that exposure to extremely low frequency magnetic fields (ELF MFs) influences human electroencephalographic (EEG) alpha activity and pain perception. In the present study we analyse the effect on electrical EEG activity in the alpha band (8-13 Hz) and on nociception in 40 healthy male volunteers after 90-min exposure of the head to 50 Hz ELF MFs at a flux density of 40 or 80 microT in a double-blind randomized sham-controlled study. Since cardiovascular regulation is functionally related to pain modulation, we also measured blood pressure (BP) and heart rate (HR) during treatment. Alpha activity after 80 microT magnetic treatment almost doubled compared to sham treatment. Pain threshold after 40 microT magnetic treatment was significantly lower than after sham treatment. No effects were found for BP and HR. We suggest that these results may be explained by a modulation of sensory gating processes through the opioidergic system, that in turn is influenced by magnetic exposure.
Collapse
Affiliation(s)
- Sergio Ghione
- Institute of Clinical Physiology, National Council of Research, Area S. Cataldo, Via Moruzzi, 1, 56124 Pisa, Italy.
| | | | | | | |
Collapse
|
11
|
Qin C, Evans JM, Yamanashi WS, Scherlag BJ, Foreman RD. Effects on rats of low intensity and frequency electromagnetic field stimulation on thoracic spinal neurons receiving noxious cardiac and esophageal inputs. Neuromodulation 2005; 8:79-87. [PMID: 22151436 DOI: 10.1111/j.1525-1403.2005.00223.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Objective Low intensity and low frequency electromagnetic field stimulation (EMFs) provides substantial pain relief in patients with various chronic pains. The aim of this study was to examine the effects of EMFs on the activity of thoracic spinal neurons responding to noxious visceral stimuli. Materials and Methods Extracellular potentials of single T(3) -T(4) spinal neurons were recorded in pentobarbital anesthetized male rats. A catheter was placed in the pericardial sac to administer a mixture of algogenic chemicals for noxious cardiac stimulation (0.2 mL, 1 min). Noxious esophageal distension was produced by water inflation (0.4 mL, 20 sec) of a latex balloon. EMFs (0.839-0.952 Hz, 0.030-0.034 µG, 30-40 min) was applied with a pair of Helmholtz coils placed on both sides of the chest. Results After the onset of EMFs, excitatory neuronal responses to intrapericardial chemicals were reduced in 24/32 (75%) spinal neurons, increased in three neurons and were not affected in five neurons. The inhibitory effect on spinal neurons occurred 10-20 min after the onset of EMFs. Even after termination of EMFs, the suppression of spinal neuronal activity lasted for 1-2 hr. In contrast, excitatory responses of 7/18 (39%) neurons to esophageal distension were inhibited, five (28%) were excited and six (33%) were not affected by EMFs. Conclusions Results showed that EMFs generally reduced nociceptive responses of spinal neurons to noxious cardiac chemical stimuli, whereas it was not effective for nociceptive responses to esophageal mechanical stimulation.
Collapse
Affiliation(s)
- Chao Qin
- Departments of PhysiologyMedicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | | | | | | | | |
Collapse
|
12
|
Ghione S, Del Seppia C, Mezzasalma L, Emdin M, Luschi P. Human head exposure to a 37 Hz electromagnetic field: Effects on blood pressure, somatosensory perception, and related parameters. Bioelectromagnetics 2004; 25:167-75. [PMID: 15042625 DOI: 10.1002/bem.10180] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Previous studies have shown that exposure to an electromagnetic field (EMF) of 37 Hz at a flux density of 80 microT peak enhances nociceptive sensitivity in mice. Here we examined the effects on pain sensitivity and some indexes of cardiovascular regulation mechanisms in humans by measuring electrical cutaneous thresholds, arterial blood pressure, heart rate and its variability, and stress hormones. Pain and tolerance thresholds remained unchanged after sham exposure but significantly decreased after electromagnetic exposure. Systolic blood pressure was significantly higher during electromagnetic exposure and heart rate significantly decreased, both during sham and electromagnetic exposure, while the high frequency (150-400 mHz) component of heart rate variability, which is an index of parasympathetic activity, increased as expected during sham exposure but remained unchanged during electromagnetic exposure. Cortisol significantly decreased during sham exposure only. These results show that exposure to an EMF of 37 Hz also alters pain sensitivity in humans and suggest that these effects may be associated with abnormalities in cardiovascular regulation.
Collapse
|
13
|
Del Seppia C, Mezzasalma L, Choleris E, Luschi P, Ghione S. Effects of magnetic field exposure on open field behaviour and nociceptive responses in mice. Behav Brain Res 2003; 144:1-9. [PMID: 12946589 DOI: 10.1016/s0166-4328(03)00042-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Results of previous studies have shown that nociceptive sensitivity in male C57 mice is enhanced by exposure to a regular 37 Hz or an irregularly varying (<1 Hz) electromagnetic field. In order to test whether these fields affect more generally mouse behaviour, we placed Swiss CD-1 mice in a novel environment (open field test) and exposed them for 2 h to these two different magnetic field conditions. Hence, we analysed how duration and time course of various behavioural patterns (i.e. exploration, rear, edge chew, self-groom, sit, walk and sleep) and nociceptive sensitivity had been affected by such exposure. Nociceptive sensitivity was significantly greater in magnetically treated mice than in controls. The overall time spent in exploratory activities was significantly shorter in both magnetically treated groups (< 1 Hz, 33% and 37 Hz, 29% of total time), than in controls (42%). Conversely, the time spent in sleeping was markedly longer in the treated groups (both 27% of total time) than in controls (11%). These results suggest that exposure to altered magnetic fields induce a more rapid habituation to a novel environment.
Collapse
|
14
|
Giunchi D, Pollonara E, Baldaccini N. The influence of transport conditions on the initial orientation of sand martins (Riparia riparia). ETHOL ECOL EVOL 2003. [DOI: 10.1080/08927014.2003.9522693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
15
|
Cook CM, Thomas AW, Prato FS. Human electrophysiological and cognitive effects of exposure to ELF magnetic and ELF modulated RF and microwave fields: a review of recent studies. Bioelectromagnetics 2002; 23:144-57. [PMID: 11835261 DOI: 10.1002/bem.107] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The investigation of weak (<500 microT), extremely low frequency (ELF, 0-300 Hz) magnetic field (MF) exposure upon human cognition and electrophysiology has yielded incomplete and contradictory evidence that MFs interact with human biology. This may be due to the small number of studies undertaken examining ELF MF effects upon the human electroencephalogram (EEG), and the associated analysis of evoked related potentials (ERPs). Relatively few studies have examined how MF exposure may affect cognitive and perceptual processing in human subjects. The introduction of this review considers some of the recent studies of ELF MF exposure upon the EEG, ERPs and cognitive and perceptual tasks. We also consider some of the confounding factors within current human MF studies and suggest some new strategies for further experimentation.
Collapse
Affiliation(s)
- C M Cook
- Lawson Health Research Institute, Department of Nuclear Medicine MR, St Joseph's Health Care, London, Ontario, Canada.
| | | | | |
Collapse
|
16
|
Choleris E, Del Seppia C, Thomas AW, Luschi P, Ghione G, Moran GR, Prato FS. Shielding, but not zeroing of the ambient magnetic field reduces stress-induced analgesia in mice. Proc Biol Sci 2002; 269:193-201. [PMID: 11798436 PMCID: PMC1690875 DOI: 10.1098/rspb.2001.1866] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Magnetic field exposure was consistently found to affect pain inhibition (i.e. analgesia). Recently, we showed that an extreme reduction of the ambient magnetic and electric environment, by mu-metal shielding, also affected stress-induced analgesia (SIA) in C57 mice. Using CD1 mice, we report here the same findings from replication studies performed independently in Pisa, Italy and London, ON, Canada. Also, neither selective vector nulling of the static component of the ambient magnetic field with Helmholtz coils, nor copper shielding of only the ambient electric field, affected SIA in mice. We further show that a pre-stress exposure to the mu-metal box is necessary for the anti-analgesic effects to occur. The differential effects of the two near-zero magnetic conditions may depend on the elimination (obtained only by mu-metal shielding) of the extremely weak time-varying component of the magnetic environment. This would provide the first direct and repeatable evidence for a behavioural and physiological effect of very weak time-varying magnetic fields, suggesting the existence of a very sensitive magnetic discrimination in the endogenous mechanisms that underlie SIA. This has important implications for other reported effects of exposures to very weak magnetic fields and for the theoretical work that considers the mechanisms underlying the biological detection of weak magnetic fields.
Collapse
Affiliation(s)
- E Choleris
- Lawson Health Research Institute, St Joseph's Health Centre and University of Western Ontario, 268 Grosvenor Street, London, ON, Canada N6A 4V2.
| | | | | | | | | | | | | |
Collapse
|
17
|
Thomas AW, Drost DJ, Prato FS. Magnetic field exposure and behavioral monitoring system. Bioelectromagnetics 2001; 22:401-7. [PMID: 11536281 DOI: 10.1002/bem.67] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
To maximize the availability and usefulness of a small magnetic field exposure laboratory, we designed a magnetic field exposure system that has been used to test human subjects, caged or confined animals, and cell cultures. The magnetic field exposure system consists of three orthogonal pairs of coils 2 m square x 1 m separation, 1.751 m x 0.875 m separation, and 1.5 m x 0.75 m separation. Each coil consisted of ten turns of insulated 8 gauge stranded copper conductor. Each of the pairs were driven by a constant-current amplifier via digital to analog (D/A) converter. A 9 pole zero-gain active Bessel low-pass filter (1 kHz corner frequency) before the amplifier input attenuated the expected high frequencies generated by the D/A conversion. The magnetic field was monitored with a 3D fluxgate magnetometer (0-3 kHz, +/- 1 mT) through an analog to digital converter. Behavioral monitoring utilized two monochrome video cameras (viewing the coil center vertically and horizontally), both of which could be video recorded and real-time digitally Moving Picture Experts Group (MPEG) encoded to CD-ROM. Human postural sway (standing balance) was monitored with a 3D forceplate mounted on the floor, connected to an analog to digital converter. Lighting was provided by 12 offset overhead dimmable fluorescent track lights and monitored using a digitally connected spectroradiometer. The dc resistance, inductance of each coil pair connected in series were 1.5 m coil (0.27 Omega, 1.2 mH), 1.75 m coil (0.32 Omega, 1.4 mH), and 2 m coil (0.38 Omega, 1.6 mH). The frequency response of the 1.5 m coil set was 500 Hz at +/- 463 microT, 1 kHz at +/- 232 microT, 150 micros rise time from -200 microT(pk) to + 200 microT(pk) (square wave) and is limited by the maximum voltage ( +/- 146 V) of the amplifier (Bessel filter bypassed).
Collapse
Affiliation(s)
- A W Thomas
- Bioelectromagnetics Western, Department of Nuclear Medicine & MR, The Lawson Health Research Institute, St. Joseph's Health Care, London, Ontario, Canada N6A 4V2.
| | | | | |
Collapse
|
18
|
|
19
|
Prato FS, Kavaliers M, Cullen AP, Thomas AW. Light-dependent and -independent behavioral effects of extremely low frequency magnetic fields in a land snail are consistent with a parametric resonance mechanism. Bioelectromagnetics 2000; 18:284-91. [PMID: 9096848 DOI: 10.1002/(sici)1521-186x(1997)18:3<284::aid-bem13>3.0.co;2-p] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Exposure to extremely low frequency (ELF) magnetic fields has been shown to attenuate endogenous opioid peptide mediated antinociception or "analgaesia" in the terrestrial pulmonate snail, Cepaea nemoralis. Here we examine the roles of light in determining this effect and address the mechanisms associated with mediating the effects of the ELF magnetic fields in both the presence and absence of light. Specifically, we consider whether the magnetic field effects involve an indirect induced electric current mechanism or a direct effect such as a parametric resonance mechanism (PRM). We exposed snails in both the presence and absence of light at three different frequencies (30, 60, and 120 Hz) with static field values (BDC) and ELF magnetic field amplitude (peak) and direction (BAC) set according to the predictions of the PRM for Ca2+. Analgaesia was induced in snails by injecting them with an enkephalinase inhibitor, which augments endogenous opioid (enkephalin) activity. We found that the magnetic field exposure reduced this opioid-induced analgaesia significantly more if the exposure occurred in the presence rather than the absence of light. However, the percentage reduction in analgaesia in both the presence and absence of light was not dependent on the ELF frequency. This finding suggests that in both the presence and the absence of light the effect of the ELF magnetic field was mediated by a direct magnetic field detection mechanism such as the PRM rather than an induced current mechanism.
Collapse
Affiliation(s)
- F S Prato
- Bioelectromagnetics Western, University of Western Ontario, Canada.
| | | | | | | |
Collapse
|
20
|
Prato FS, Kavaliers M, Thomas AW. Extremely low frequency magnetic fields can either increase or decrease analgaesia in the land snail depending on field and light conditions. Bioelectromagnetics 2000; 21:287-301. [PMID: 10797457 DOI: 10.1002/(sici)1521-186x(200005)21:4<287::aid-bem5>3.0.co;2-n] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Results of prior investigations with opioid peptide mediated antinociception or analgaesia have suggested that these extremely low frequency (ELF) magnetic field effects are described by a resonance mechanism rather than mechanisms based on either induced currents or magnetite. Here we show that ELF magnetic fields (141-414 microT peak) can, in a manner consistent with the predictions of Lednev's parametric resonance model (PRM) for the calcium ion, either (i) reduce, (ii) have no effect on, or (iii) increase endogenous opioid mediated analgaesia in the land snail, Cepaea nemoralis. When the magnetic fields were set to parameters for the predictions of the PRM for the potassium ion, opioid-peptide mediated analgaesia increased and there was evidence of antagonism by the K(+) channel blocker, glibenclamide. Furthermore, these effects were dependent on the presence of light; the effects were absent in the absence of light. These observed increases and decreases in opioid analgaesia are largely consistent with the predictions of Lednev's PRM.
Collapse
Affiliation(s)
- F S Prato
- Lawson Research Institute, University of Western Ontario, Canada.
| | | | | |
Collapse
|
21
|
Del Seppia C, Luschi P, Ghione S, Crosio E, Choleris E, Papi F. Exposure to a hypogeomagnetic field or to oscillating magnetic fields similarly reduce stress-induced analgesia in C57 male mice. Life Sci 2000; 66:1299-306. [PMID: 10755465 DOI: 10.1016/s0024-3205(00)00437-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Previous studies have shown that exposure to altered magnetic fields alters analgesic responses in a variety of species, including humans. Here we examined whether deprivation of the normally occurring geomagnetic field also affects stress-induced analgesia, by measuring the nociceptive responses of C57 male mice that were restraint-stressed in a hypogeomagnetic environment (inside a mu-metal box). Stress-induced analgesia was significantly suppressed in a manner comparable to that observed in mice that were either exposed to altered oscillating magnetic fields or treated with the prototypic opiate antagonist naloxone. These results represent the first piece of evidence that a period in a hypogeomagnetic environment inhibits stress-induced analgesia.
Collapse
Affiliation(s)
- C Del Seppia
- Institute of Clinical Physiology, CNR, Pisa, Italy.
| | | | | | | | | | | |
Collapse
|
22
|
Seaman RL, Belt ML, Doyle JM, Mathur SP. Hyperactivity caused by a nitric oxide synthase inhibitor is countered by ultra-wideband pulses. Bioelectromagnetics 1999; 20:431-9. [PMID: 10495308 DOI: 10.1002/(sici)1521-186x(199910)20:7<431::aid-bem4>3.0.co;2-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Potential action of ultra-wideband (UWB) electromagnetic field pulses on effects of N(G)-nitro- L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase (NOS), on nociception and locomotor activity was investigated in CF-1 mice. Animals were injected IP with saline or 50 mg/kg L-NAME and exposed for 30 min to no pulses (sham exposure) or UWB pulses with electric field parameters of 102+/-1 kV/m peak amplitude, 0.90+/-0.05 ns duration, and 160+/-5 ps rise time (mean+/-S.D.) at 600/s. Animals were tested for thermal nociceptive responses on a 50 degrees C surface and for spontaneous locomotor activity for 5 min. L-NAME by itself increased mean first-response (paw lift, shake, or lick; jump) and back-paw-lick response latencies and mean locomotor activity. Exposure to UWB pulses reduced the L-NAME-induced increase in back-paw-lick latency by 22%, but this change was not statistically significant. The L-NAME-induced hyperactivity was not present after UWB exposure. Reduction and cancellation of effects of L-NAME suggest activation of opposing mechanism(s) by the UWB pulses, possibly including increase of nitric oxide production by NOS. The action, or actions, of UWB pulses appears to be more effective on locomotor activity than on thermal nociception in CF-1 mice.
Collapse
Affiliation(s)
- R L Seaman
- McKesson BioServices and Microwave Bioeffects Branch, U.S. Army Medical Research Detachment, Brooks AFB, Texas 78235-5460, USA.
| | | | | | | |
Collapse
|
23
|
Beers GJ, Phillips JL, Prato FS, Nair I. BIOLOGIC EFFECTS OF LOW-LEVEL ELECTROMAGNETIC FIELDS. Magn Reson Imaging Clin N Am 1998. [DOI: 10.1016/s1064-9689(21)00480-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
24
|
Kavaliers M, Choleris E, Prato FS, Ossenkopp K. Evidence for the involvement of nitric oxide and nitric oxide synthase in the modulation of opioid-induced antinociception and the inhibitory effects of exposure to 60-Hz magnetic fields in the land snail. Brain Res 1998; 809:50-7. [PMID: 9795129 DOI: 10.1016/s0006-8993(98)00844-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The attenuation of opioid peptide-mediated antinociception is a well-established effect of extremely low frequency (ELF) electromagnetic fields with alterations in calcium channel function and/or calcium ion flux and protein kinase C activity being implicated in the mediation of these effects. The present study was designed to examine the effects of nitric oxide (NO) and calcium ion/calmodulin-dependent nitric oxide synthase (NOS) on opioid-induced antinociception and their involvement in mediating the inhibitory effects of exposure to ELF magnetic fields. We observed that enkephalinase (SCH 34826)-induced, and likely enkephalin-mediated, antinociception in the land snail, Cepaea nemoralis, as measured by the enhanced latency of a foot withdrawal response to a thermal (40 degreesC) stimulus, was reduced by the NO releasing agent, S-nitro-N-acetylpenicillamide (SNP), and enhanced by the NO synthase inhibitor, NG-nitro-l-arginine methyl ester (l-NAME). Exposure of snails to an ELF magnetic field (15 min, 60 Hz, 141 microT peak) also reduced the enkephalinase-induced antinociception. The inhibitory effects of the 60-Hz magnetic field were significantly reduced by the NO synthase inhibitor, l-NAME, and significantly enhanced by the NO releasing agent, SNP, at dosages which by themselves had no evident effects on nociceptive sensitivity. These results suggest that: (1) NO and NO synthase have antagonistic effects on opioid-induced analgesia in the snail, Cepaea and (2) the inhibitory effects of ELF magnetic fields on opioid analgesia involve alteration in NO and NO synthase activity.
Collapse
Affiliation(s)
- M Kavaliers
- Department of Psychology, Social Sciences Centre, University of Western Ontario, London, Ontario, Canada.
| | | | | | | |
Collapse
|
25
|
Prato FS, Kavaliers M, Thomas AW, Ossenkopp KP. Modulatory actions of light on the behavioural responses to magnetic fields by land snails probably occur at the magnetic field detection stage. Proc Biol Sci 1998. [DOI: 10.1098/rspb.1998.0304] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- F. S. Prato
- Bioelectromagnetics Western, University of Western Ontario, Department of Nuclear Medicine & Magnetic Resonance, StJoseph's Health Centre, Lawson Research Institute, 268 Grosvenor Street, London, Ontario, N6A 4V2, Canada
| | - M. Kavaliers
- Division of Oral Biology, School of Dentistry, St Joseph's Health Centre, Lawson Research Institute, 268 Grosvenor Street, London, Ontario, Canada
- Department of Psychology and NeuroScience Programme, St Joseph's Health Centre, Lawson Research Institute, 268 Grosvenor Street, London, Ontario, N6A 4V2, Canada
| | - A. W. Thomas
- Bioelectromagnetics Western, University of Western Ontario, Department of Nuclear Medicine & Magnetic Resonance, StJoseph's Health Centre, Lawson Research Institute, 268 Grosvenor Street, London, Ontario, N6A 4V2, Canada
| | - K.-P. Ossenkopp
- Department of Psychology and NeuroScience Programme, St Joseph's Health Centre, Lawson Research Institute, 268 Grosvenor Street, London, Ontario, N6A 4V2, Canada
| |
Collapse
|
26
|
Thomas AW, Kavaliers M, Prato FS, Ossenkopp KP. Analgesic effects of a specific pulsed magnetic field in the land snail, Cepaea nemoralis: consequences of repeated exposures, relations to tolerance and cross-tolerance with DPDPE. Peptides 1998; 19:333-42. [PMID: 9493866 DOI: 10.1016/s0196-9781(97)00380-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
It has been demonstrated previously that a short acute exposure to a specific extremely low frequency pulsed magnetic field (Cnp) can induce significant partly opioid-mediated analgesia in the land snail, Cepaea nemoralis. Here, this Cnp-induced analgesia is examined for the development of tolerance to daily repeated acute exposures of 15 or 30 min duration. Acute cross-tolerance to the delta opioid receptor directed agonist DPDPE, [D-Pen2, D-Pen5]enkephalin, was also found. Before (pre-exposure) and after (0, 15, 30 and 60 min) exposure to either a sham or Cnp magnetic field, snails were tested for an aversive reaction to a warmed surface (40 degrees C), and the latency time to the aversive reaction was recorded. Snails that were exposed to the Cnp showed a significant increase in the latency time (F1.55 = 2856.4; p < 0.001; Eta2 = 0.95), which may be interpreted as an induction of analgesia. During the daily (9 day) repeated acute exposures, the induction of analgesic response was significantly reduced, but not ablated. Altering the environmental conditions of the Cnp exposure restored a significant proportion of the partly developed tolerance, consistent with previous reports of environmental specificity in the development of opioid tolerance. These findings suggest that the partial development of tolerance to the opioid-mediated portion of Cnp-induced analgesia may be countered by altering the specific environmental Cnp exposure conditions.
Collapse
Affiliation(s)
- A W Thomas
- Neuroscience Program, University of Western Ontario, London, Canada.
| | | | | | | |
Collapse
|
27
|
Sartucci F, Bonfiglio L, Del Seppia C, Luschi P, Ghione S, Murri L, Papi F. Changes in pain perception and pain-related somatosensory evoked potentials in humans produced by exposure to oscillating magnetic fields. Brain Res 1997; 769:362-6. [PMID: 9374207 DOI: 10.1016/s0006-8993(97)00755-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Nociception has been reported to be influenced by exposure to magnetic fields (MFs). The aim of this study was to investigate the effects of 2 h exposure to weak, oscillating MFs on pain perception thresholds and on pain-related somatosensory evoked potentials (SEPs). In 11 healthy volunteers, pain perception thresholds and pain-related SEPs were assessed by intracutaneous electrical stimulation. After sham treatment, pain thresholds significantly increased, whereas after MFs a slight non-significant decrease in thresholds was found. After both treatments pain-related SEP amplitude was reduced, but this decrease was more evident and statistically significant only after MF exposure. The increase found in thresholds after sham exposure may be due to stress-induced analgesia (SIA) and the contrasting behaviour recorded after MF exposure might indicate a suppression of SIA. The significant reduction in pain-related SEP amplitude observed after MF exposure provides the first evidence that human SEPs are influenced by MFs.
Collapse
Affiliation(s)
- F Sartucci
- Department of Neurosciences, University of Pisa, Italy
| | | | | | | | | | | | | |
Collapse
|
28
|
Thomas AW, Kavaliers M, Prato FS, Ossenkopp KP. Antinociceptive effects of a pulsed magnetic field in the land snail, Cepaea nemoralis. Neurosci Lett 1997; 222:107-10. [PMID: 9111740 DOI: 10.1016/s0304-3940(97)13359-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Pulsed magnetic fields (patent pending) consisting of approximately 100 microT (peak), frequency modulated, extremely low frequency magnetic fields (ELFMF) were shown to induce a significant degree of antinociception ('analgesia') in the land snail Cepaea nemoralis. Fifteen minute exposures to a specific magnetic field both increased enkephalinase inhibitor induced opioid analgesia and induced analgesia in untreated snails. Injection of the prototypic opioid antagonist naloxone, attenuated, but did not completely block, the pulsed magnetic field induced analgesia. Two other pulsed waveform designs failed to induce analgesia in untreated snails. These findings suggest that specific magnetic field exposure designs may be tailored to produce significant behavioral effects including, but certainly not limited to, the induction of analgesia.
Collapse
Affiliation(s)
- A W Thomas
- Neuroscience Program, University of Western Ontario, London, Canada.
| | | | | | | |
Collapse
|
29
|
Pigeon homing: evidence against reliance on magnetic information picked up en route to release sites. Proc Biol Sci 1997. [DOI: 10.1098/rspb.1996.0179] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
30
|
Thomas AW, Kavaliers M, Prato FS, Ossenkopp KP. Pulsed magnetic field induced "analgesia" in the land snail, Cepaea nemoralis, and the effects of mu, delta, and kappa opioid receptor agonists/antagonists. Peptides 1997; 18:703-9. [PMID: 9213364 DOI: 10.1016/s0196-9781(97)00004-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A brief exposure to a pulsed magnetic field (Cnp: patent pending) had significant antinociceptive or "analgesic" effects in the land snail, Cepaea nemoralis, as evidenced by an increase in the latency of response to a warmed (40 degrees C) surface. This analgesia was in part opioid mediated being significantly reduced, but not eliminated: by the prototypic opiate antagonist, naloxone; the mu (mu) opioid receptor directed antagonists, naloxazine or beta-funaltrexamine, and the delta (delta) opioid receptor directed antagonists, naltrindole-5'-isothiocyanate or ICI 174,864. However the Cnp induced analgesia was unaffected by the kappa (kappa) opioid receptor directed antagonist, nor-binaltorphimine. The delta 1 and delta 2 opioid receptor directed agonists, (DPDPE, [D-Pen2,D-Pen5]enkephalin), (deltorphin, [D-Ala2,Glu4]), respectively, also had significant differential analgesic effects, supporting a functional delta opioid receptor mediated enkephalinergic mechanism in Cepaea. These results suggest that this specific pulsed magnetic field (Cnp) elicits significant analgesic effects through mechanisms that, in part, involve delta and, to a lesser extent mu opioid receptors.
Collapse
MESH Headings
- Analgesia
- Animals
- Electromagnetic Fields/adverse effects
- Enkephalin, D-Penicillamine (2,5)-
- Enkephalins/pharmacology
- Enkephalins/radiation effects
- Naloxone/pharmacology
- Narcotic Antagonists
- Oligopeptides/pharmacology
- Oligopeptides/radiation effects
- Reaction Time/drug effects
- Reaction Time/radiation effects
- Receptors, Opioid/agonists
- Receptors, Opioid/radiation effects
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/radiation effects
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/antagonists & inhibitors
- Receptors, Opioid, kappa/radiation effects
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/radiation effects
- Snails
Collapse
Affiliation(s)
- A W Thomas
- Neuroscience Program, Faculty of Dentistry, University of Western Ontario, London, Canada.
| | | | | | | |
Collapse
|
31
|
Kavaliers M, Ossenkopp KP, Prato FS, Innes DG, Galea LA, Kinsella DM, Perrot-Sinal TS. Spatial learning in deer mice: sex differences and the effects of endogenous opioids and 60 Hz magnetic fields. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1996; 179:715-24. [PMID: 8888582 DOI: 10.1007/bf00216135] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We examined the effects of brief exposure to weak 60 Hz extremely low frequency (ELF) magnetic fields and opioid systems on spatial behavior and learning in reproductive adult male and female deer mice, Peromyscus maniculatus. Sex differences were evident in spatial performance, with male deer mice displaying significantly better performance than female mice in the Morris water maze, whereby animals had to acquire and retain the location of a submerged hidden platform. Brief (maximum 5 min) exposure to weak (100 microT) 60 Hz magnetic fields during task acquisition significantly improved female performance, eliminating the sex differences in acquisition. The opiate antagonist, naltrexone, also improved female acquisition, though significantly less than the magnetic fields. These facilitatory effects involved alterations of "non-spatial" (task familiarization and reduction of related anxiety/aversive related behaviors) and possibly "spatial" aspects of the task. Enhancement of enkephalin activity with the enkephalinase inhibitor, SCH 34826, significantly reduced task performance by male deer mice. Both naltrexone and the 60 Hz magnetic fields attenuated the enkephalin mediated reductions of spatial performance. These findings indicate that brief exposure to 60 Hz magnetic fields can enhance water maze task acquisition by deer mice and suggest that these facilitatory effects on spatial performance involve alterations in opioid activity.
Collapse
Affiliation(s)
- M Kavaliers
- Faculty of Dentistry, Department of Psychology, University of Western Ontario, London, Canada.
| | | | | | | | | | | | | |
Collapse
|
32
|
Papi F, Ghione S, Rosa C, Del Seppia C, Luschi P. Exposure to oscillating magnetic fields influences sensitivity to electrical stimuli. II. Experiments on humans. Bioelectromagnetics 1995; 16:295-300. [PMID: 8554630 DOI: 10.1002/bem.2250160505] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To assess the effect of a magnetic treatment on pain perception, we compared the sensory threshold in 18 healthy volunteers. We determined the threshold by noninvasive electrical stimulation of the tooth pulp and skin before and after exposure to an altered magnetic field of low intensity and to a sham treatment. Five different parameters were recorded: the sensory and pain thresholds for the tooth and the sensory, pain, and tolerance thresholds for the skin. Two hours of exposure to a weak, oscillating magnetic fields induced a significant decrease in three parameters (dental sensory and cutaneous pain and tolerance thresholds), whereas the other two parameters showed a similar tendency. When the same subjects were exposed to a sham treatment, only marginal, nonsignificant variations in all parameters were observed. These results represent the first piece of evidence that weak alterations of the magnetic field may induce hyperalgesia in humans.
Collapse
Affiliation(s)
- F Papi
- Dipartimento di Scienze del Comportamento Animale e dell'Uomo, Universitá di Pisa, Italy
| | | | | | | | | |
Collapse
|