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The Effect of a Single 30-Min Long Term Evolution Mobile Phone-Like Exposure on Thermal Pain Threshold of Young Healthy Volunteers. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15091849. [PMID: 30150567 PMCID: PMC6165439 DOI: 10.3390/ijerph15091849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 08/22/2018] [Accepted: 08/23/2018] [Indexed: 11/26/2022]
Abstract
Although the majority of mobile phone (MP) users do not attribute adverse effects on health or well-being to MP-emitted radiofrequency (RF) electromagnetic fields (EMFs), the exponential increase in the number of RF devices necessitates continuing research aimed at the objective investigation of such concerns. Here we investigated the effects of acute exposure from Long Term Evolution (LTE) MP EMFs on thermal pain threshold in healthy young adults. We use a protocol that was validated in a previous study in a capsaicin-induced hyperalgesia model and was also successfully used to show that exposure from an RF source mimicking a Universal Mobile Telecommunications System (UMTS) MP led to mildly stronger desensitization to repeated noxious thermal stimulation relative to the sham condition. Using the same experimental design, we did not find any effects of LTE exposure on thermal pain threshold. The present results, contrary to previous evidence obtained with the UMTS modulation, are likely to originate from placebo/nocebo effects and are unrelated to the brief acute LTE EMF exposure itself. The fact that this is dissimilar to our previous results on UMTS exposure implies that RF modulations might differentially affect pain perception and points to the necessity of further research on the topic.
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Maliszewska J, Marciniak P, Kletkiewicz H, Wyszkowska J, Nowakowska A, Rogalska J. Electromagnetic field exposure (50 Hz) impairs response to noxious heat in American cockroach. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:605-611. [PMID: 29721708 PMCID: PMC5966488 DOI: 10.1007/s00359-018-1264-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/20/2018] [Accepted: 04/21/2018] [Indexed: 11/29/2022]
Abstract
Exposure to electromagnetic field (EMF) induces physiological changes in organism that are observed at different levels—from biochemical processes to behavior. In this study, we evaluated the effect of EMF exposure (50 Hz, 7 mT) on cockroach’s response to noxious heat, measured as the latency to escape from high ambient temperature. We also measured the levels of lipid peroxidation and glutathione content as markers of oxidative balance in cockroaches exposed to EMF. Our results showed that exposure to EMF for 24, 72 h and 7 days significantly increases the latency to escape from noxious heat. Malondialdehyde (MDA) levels increased significantly after 24-h EMF exposure and remained elevated up to 7 days of exposure. Glutathione levels significantly declined in cockroaches exposed to EMF for 7 days. These results demonstrate that EMF exposure is a considerable stress factor that affects oxidative state and heat perception in American cockroach.
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Affiliation(s)
- Justyna Maliszewska
- Department of Animal Physiology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, ul. Lwowska 1, 87-100, Toruń, Poland.
| | | | - Hanna Kletkiewicz
- Department of Animal Physiology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, ul. Lwowska 1, 87-100, Toruń, Poland
| | - Joanna Wyszkowska
- Department of Biophysics, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Anna Nowakowska
- Department of Animal Physiology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, ul. Lwowska 1, 87-100, Toruń, Poland
| | - Justyna Rogalska
- Department of Animal Physiology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University, ul. Lwowska 1, 87-100, Toruń, Poland
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Jadidi M, Khatami MS, Mohammad-pour F, Bandavi A, Rashidy-pour A, Vafaei AA, Taherian AA, Miladi-Gorji H. Effects of extremely low frequency magnetic field on the development of tolerance to the analgesic effect of morphine in rats. Bioelectromagnetics 2017; 38:618-625. [DOI: 10.1002/bem.22089] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Accepted: 09/05/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Majid Jadidi
- Research Center of Physiology and Department of Medical Physics; School of Medicine; Semnan University of Medical Sciences; Semnan Iran
| | - Mahfouzeh Sadat Khatami
- Research Center and Department of Physiology; School of Medicine; Semnan University of Medical Sciences; Semnan Iran
| | - Fatemeh Mohammad-pour
- Research Center and Department of Physiology; School of Medicine; Semnan University of Medical Sciences; Semnan Iran
| | - Afsaneh Bandavi
- Research Center and Department of Physiology; School of Medicine; Semnan University of Medical Sciences; Semnan Iran
| | - Ali Rashidy-pour
- Research Center and Department of Physiology; School of Medicine; Semnan University of Medical Sciences; Semnan Iran
| | - Abbas Ali Vafaei
- Research Center and Department of Physiology; School of Medicine; Semnan University of Medical Sciences; Semnan Iran
| | - Abbas Ali Taherian
- Research Center and Department of Physiology; School of Medicine; Semnan University of Medical Sciences; Semnan Iran
| | - Hossein Miladi-Gorji
- Research Center and Department of Physiology; School of Medicine; Semnan University of Medical Sciences; Semnan Iran
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4
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Vecsei Z, Csathó Á, Thuróczy G, Hernádi I. Effect of a single 30 min UMTS mobile phone-like exposure on the thermal pain threshold of young healthy volunteers. Bioelectromagnetics 2013; 34:530-41. [PMID: 23787775 DOI: 10.1002/bem.21801] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 05/09/2013] [Indexed: 11/06/2022]
Abstract
One of the most frequently investigated effects of radiofrequency electromagnetic fields (RF EMFs) on the behavior of complex biological systems is pain sensitivity. Despite the growing body of evidence of EMF-induced changes in pain sensation, there is no currently accepted experimental protocol for such provocation studies for the healthy human population. In the present study, therefore, we tested the effects of third generation Universal Mobile Telecommunications System (UMTS) RF EMF exposure on the thermal pain threshold (TPT) measured on the surface of the fingers of 20 young adult volunteers. The protocol was initially validated with a topical capsaicin treatment. The exposure time was 30 min and the genuine (or sham) signal was applied to the head through a patch antenna, where RF EMF specific absorption rate (SAR) values were controlled and kept constant at a level of 1.75 W/kg. Data were obtained using randomized, placebo-controlled trials in a double-blind manner. Subjective pain ratings were tested blockwise on a visual analogue rating scale (VAS). Compared to the control and sham conditions, the results provide evidence for intact TPT but a reduced desensitization effect between repeated stimulations within the individual blocks of trials, observable only on the contralateral side for the genuine UMTS exposure. Subjective pain perception (VAS) data indicated marginally decreased overall pain ratings in the genuine exposure condition only. The present results provide pioneering information about human pain sensation in relation to RF EMF exposure and thus may contribute to cover the existing gap between safety research and applied biomedical science targeting the potential biological effects of environmental RF EMFs.
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Affiliation(s)
- Zsuzsanna Vecsei
- Department of Experimental Neurobiology, Faculty of Sciences, University of Pécs, Pécs, Hungary; National Research Institute for Radiobiology and Radiohygiene (NRIRR), Budapest, Hungary
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Kiss B, Gyires K, Kellermayer M, László JF. Lateral gradients significantly enhance static magnetic field-induced inhibition of pain responses in mice--a double blind experimental study. Bioelectromagnetics 2013; 34:385-96. [PMID: 23737187 DOI: 10.1002/bem.21781] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 01/04/2013] [Indexed: 11/10/2022]
Abstract
Recent research demonstrated that exposure of mice to both inhomogeneous (3-477 mT) and homogeneous (145 mT) static magnetic fields (SMF) generated an analgesic effect toward visceral pain elicited by the intraperitoneal injection of 0.6% acetic acid. In the present work, we investigated behavioral responses such as writhing, entry avoidance, and site preference with the help of a specially designed cage that partially protruded into either the homogeneous (ho) or inhomogeneous (inh) SMF. Aversive effects, cognitive recognition of analgesia, and social behavior governed mice in their free locomotion between SMF and sham sides. The inhibition of pain response (I) for the 0-5, 6-20, and 21-30 min periods following the challenge was calculated by the formula I = 100 (1 - x/y) in %, where x and y represent the number of writhings in the SMF and sham sides, respectively. In accordance with previous measurements, an analgesic effect was induced in exposed mice (Iho = 64%, P < 0.0002 and Iinh = 62%, P < 0.002). No significant difference was found in the site preference (SMFho, inh vs. sham) indicating that SMF is neither aversive nor favorable. Comparison of writhings observed in the sham versus SMF side of the cage revealed that SMF exposure resulted in significantly fewer writhings than sham (Iho = 64%, P < 0.004 and Iinh = 81%, P < 0.03). Deeper statistical analysis clarified that the lateral SMF gradient between SMF and sham sides could be responsible for most of the analgesic effect (Iho = 91%, P < 0.02 and Iinh = 54%, P < 0.02).
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Affiliation(s)
- Balázs Kiss
- Department of Biophysics and Radiation Biology, Semmelweis University and MTA-SE Molecular Biophysics Research Group, Budapest, Hungary.
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6
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Nittby H, Moghadam MK, Sun W, Malmgren L, Eberhardt J, Persson BR, Salford LG. Analgetic effects of non-thermal GSM-1900 radiofrequency electromagnetic fields in the land snailHelixpomatia. Int J Radiat Biol 2011; 88:245-52. [DOI: 10.3109/09553002.2012.644257] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Whissell PD, Persinger MA. Emerging synergisms between drugs and physiologically-patterned weak magnetic fields: implications for neuropharmacology and the human population in the twenty-first century. Curr Neuropharmacol 2010; 5:278-88. [PMID: 19305744 PMCID: PMC2644491 DOI: 10.2174/157015907782793603] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 03/30/2007] [Accepted: 09/17/2007] [Indexed: 11/22/2022] Open
Abstract
Synergisms between pharmacological agents and endogenous neurotransmitters are familiar and frequent. The present review describes the experimental evidence for interactions between neuropharmacological compounds and the classes of weak magnetic fields that might be encountered in our daily environments. Whereas drugs mediate their effects through specific spatial (molecular) structures, magnetic fields mediate their effects through specific temporal patterns. Very weak (microT range) physiologically-patterned magnetic fields synergistically interact with drugs to strongly potentiate effects that have classically involved opiate, cholinergic, dopaminergic, serotonergic, and nitric oxide pathways. The combinations of the appropriately patterned magnetic fields and specific drugs can evoke changes that are several times larger than those evoked by the drugs alone. These novel synergisms provide a challenge for a future within an electromagnetic, technological world. They may also reveal fundamental, common physical mechanisms by which magnetic fields and chemical reactions affect the organism from the level of fundamental particles to the entire living system.
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Affiliation(s)
- P D Whissell
- Neuroscience Research Group, Department of Biology, Laurentian University, Sudbury, Ontario, Canada
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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]
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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.
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Affiliation(s)
- Cristina Del Seppia
- Institute of Clinical Physiology, National Council of Research, Pisa, Italy.
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McKay BE, Persinger MA. Lithium ion "cyclotron resonance" magnetic fields decrease seizure onset times in lithium-pilocarpine seized rats. Int J Neurosci 2005; 114:1035-45. [PMID: 15527207 DOI: 10.1080/00207450490461350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The cyclotron resonance equation predicts that the frequency of an applied magnetic field that might optimally interact with a single ion species may be computed as a function of the charge-to-mass ratio of the ion and the strength of the background static magnetic field. The present study was undertaken to discern the applicability of this equation for optimizing lithium ion utilization in the rat, as inferred by the predicted magnetic "ion resonance "field-induced shift of lithium's dose-dependent curve for seizure onset times (SOTs) when combined with the cholinergic agent pilocarpine. Groups of rats were administered 1.5 thru 3 mEq/kg lithium chloride (in 0.5 mEq/kg increments) and exposed to reference conditions or to one of three intensities (70 nanoTesla, 0.8 microTesla, or 25 microTesla) of a 85 Hz magnetic field calculated to resonate with lithium ions given the background static geomagnetic field of approximately 38,000 nanoTesla (0.38 Gauss). A statistically significant quadratic relationship for SOT as a function of magnetic field intensity (irrespective of lithium dose) was noted: this U-shaped function was characterized by equal SOTs for the reference and 25 microTesla groups, with a trend toward shorter SOTs for the 70 nanoTesla and 0.8 microTesla groups. Although not predicted by the equations, this report extends other findings suggestive of discrete intensity windows for which magnetic field frequencies derived from the cyclotron ion resonance equation may affect ion activity.
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Affiliation(s)
- B E McKay
- Behavioral Neuroscience Laboratory, Laurentian University, Sudbury, Ontario, Canada
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11
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McKay BE, Persinger MA. Combined effects of complex magnetic fields and agmatine for contextual fear learning deficits in rats. Life Sci 2003; 72:2489-98. [PMID: 12650857 DOI: 10.1016/s0024-3205(03)00140-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Acute post-training exposures to weak intensity theta-burst stimulation (TBS) patterned complex magnetic fields attenuated the magnitude of conditioned fear learning for contextual stimuli. A similar learning impairment was evoked in a linear and dose-dependent manner by pre-conditioning injections of the polyamine agmatine. The present study examined the hypothesis that whole-body applications of the TBS complex magnetic field pattern when co-administered with systemic agmatine treatment may combine to evoke impairments in contextual fear learning. Within minutes of 4 mg/kg agmatine injections, male Wistar rats were fear conditioned to contextual stimuli and immediately exposed for 30 min to the TBS patterned complex magnetic field or to sham conditions. TBS patterned complex magnetic field treatment was found to linearly summate with the contextual fear learning impairment evoked by agmatine treatment alone. Furthermore, we report for sham-treated rats, but not rats exposed to the synthetic magnetic field pattern, that the magnitude of learned fear decreased and the amount of variability in learning increased, as the K-index (a measure of change in intensity of the time-varying ambient geomagnetic field) increased during the 3-hr intervals over which conditioning and testing sessions were conducted.
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Affiliation(s)
- B E McKay
- Behavioral Neuroscience Laboratory, Laurentian University, Ontario, P3E 2C6, Sudbury, Canada.
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12
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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.
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Affiliation(s)
- R L Seaman
- McKesson BioServices and Microwave Bioeffects Branch, U.S. Army Medical Research Detachment, Brooks AFB, Texas 78235-5460, USA.
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Seaman RL, Belt ML, Doyle JM, Mathur SP. Ultra-wideband electromagnetic pulses and morphine-induced changes in nociception and activity in mice. Physiol Behav 1998; 65:263-70. [PMID: 9855475 DOI: 10.1016/s0031-9384(98)00165-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mice were exposed to ultra-wideband (UWB) electromagnetic pulses averaging 99-105 kV/m peak amplitude, 0.97-1.03 ns duration, and 155-174 ps rise time, after intraperitoneal administration of saline or morphine sulfate. They were then tested for thermal nociception on a 50 degrees C surface and for spontaneous locomotor activity and its time profile over 5 min. Analysis of results showed no effect of UWB exposure on nociception and activity measures in CF-1 mice after 15-, 30-, or 45-min exposure to pulses at 600/s or after 30-min exposure to UWB pulses at 60/s. Similarly, no effect was seen in C57BL/6 mice after 30-min exposure to pulses at 60/s or 600/s. Although trends in morphine-modified measures seen with UWB pulse repetition frequency could be expected because of increased levels of low-frequency energy, no significant change was seen in normal or morphine-modified nociception or activity after UWB exposure. This indicated lack of effect of the UWB pulses used in these experiments on nervous system components, including endogenous opioids, involved in these behaviors.
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Affiliation(s)
- R L Seaman
- McKesson BioServices and Microwave Bioeffects Branch, US Army Medical Research Detachment, Brooks AFB, TX 78235-5460, USA.
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Del Seppia C, Ghione S, Luschi P, Papi F. Exposure to oscillating magnetic fields influences sensitivity to electrical stimuli. I. Experiments on pigeons. Bioelectromagnetics 1995; 16:290-4. [PMID: 8554629 DOI: 10.1002/bem.2250160504] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The comparison of two measurements of the pigeon threshold for electrical stimuli, performed 2 h apart, reveals stress-induced analgesia as a result of stressful manipulations between the two tests. When pigeons are exposed to a weak, oscillating magnetic field between the two measurements, the analgesic response is inhibited and a hyperalgesic effect is recorded. The present findings are in agreement with previous studies showing that magnetic treatments may alter pigeons' emotional state and some of their behavioral patterns.
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Affiliation(s)
- C Del Seppia
- Dipartimento di Scienze del Comportamento Animale e dell'Uomo Università di Pisa, Italy
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Abstract
This paper is the fourteenth installment of our annual review of research concerning the opiate system. It includes papers published during 1991 involving the behavioral, nonanalgesic, effects of the endogenous opiate peptides. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal and renal function; mental illness and mood; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical-related activity; general activity and locomotion; sex, pregnancy, and development; immunological responses; and other behaviors.
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Affiliation(s)
- G A Olson
- Department of Psychology, University of New Orleans, LA 70148
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Kavaliers M, Ossenkopp KP, Tysdale DM. Evidence for the involvement of protein kinase C in the modulation of morphine-induced 'analgesia' and the inhibitory effects of exposure to 60-Hz magnetic fields in the snail, Cepaea nemoralis. Brain Res 1991; 554:65-71. [PMID: 1933319 DOI: 10.1016/0006-8993(91)90172-r] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
There is substantial evidence that magnetic fields can reduce opiate-induced analgesia, with alterations in calcium channel function and/or calcium ion flux being implicated in the mediation of these inhibitory effects. The present experiments were designed to examine the effects of protein kinase C (PKC), a calcium/diacylglycerol/phospholipid-dependent protein kinase, on opiate-induced analgesia and its involvement in mediating the inhibitory effects of exposure to magnetic fields. We observed that morphine-induced antinociception, or 'analgesia', in the land snail, Cepaea nemoralis, as measured by the enhanced latency of response to a thermal (38.5 degrees C) stimulus, was reduced in dose-related manner by the PKC activator, SC-9. Exposure of snails for 2 h to a low intensity (1.0 gauss rms) 60-Hz magnetic field also reduced morphine-induced analgesia. The inhibitory effects of the 60-Hz magnetic field on morphine-induced analgesia were significantly reduced by the PKC inhibitors, H-7 and H-9, and significantly enhanced by the PKC activator, SC-9. The non-specific protein kinase inhibitor, HA-1004, and the preferential calmodulin inhibitor, W-7, had no significant effects on either morphine-induced analgesia or the inhibitory actions of exposure to the magnetic fields. These results suggest that: (1) PKC has antagonistic effects on opiate-mediated analgesia in the snail, Cepaea, and (2) that the inhibitory effects of magnetic fields on opiate-induced analgesia involve alterations in PKC.
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Affiliation(s)
- M Kavaliers
- Division of Oral Biology, Faculty of Dentistry, University of Western Ontario, London, Canada
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