Extremely low frequency magnetic field modulates the level of neurotransmitters

Research on the safety risks of microwave irradiation on motion balance perception in electric power environments

To the microwave irradiation safety hazards caused by the co-construction of towers in smart grids, this paper investigates the effects of microwave irradiation in the power environment on the biological motion balance perception function. Firstly, simulation of microwave signals in the electric power environment, i.e., low-frequency harmonics and high-frequency carriers, were realized by signal modulation and applied in four types of behavior testing scenarios. Then, determining rats as target organisms to replace workers and randomly dividing into groups in proportion: open field, rotating rod fatigue, beam walking and forced swimming. Configuring radar with various parameters to match the electric power irradiation scene and stimulate rats, monitoring the abnormal behavior by image processing module, including posture, motion trajectory, distance, and other features. The experimental result showed that exposed to microwaves induce rats motor ability decline, balance perception imbalance, together with paralysis within long-term exposure, and its locomotor activity, coordination, posture control and reaction time all exhibit varying degrees of weakening. These findings indicate that microwave irradiation in electric power environment may pose significant health and safety risks for worker.

[Effects of 50 Hz electromagnetic field on rat working memory and investigation of neural mechanisms]

With the widespread use of electrical equipment, cognitive functions such as working memory (WM) could be severely affected when people are exposed to 50 Hz electromagnetic fields (EMF) for long term. However, the effects of EMF exposure on WM and its neural mechanism remain unclear. In the present paper, 15 rats were randomly assigned to three groups, and exposed to an EMF environment at 50 Hz and 2 mT for a different duration: 0 days (control group), 24 days (experimental group I), and 48 days (experimental group II). Then, their WM function was assessed by the T-maze task. Besides, their local field potential (LFP) in the media prefrontal cortex (mPFC) was recorded by the in vivo multichannel electrophysiological recording system to study the power spectral density (PSD) of θ and γ oscillations and the phase-amplitude coupling (PAC) intensity of θ-γ oscillations during the T-maze task. The results showed that the PSD of θ and γ oscillations decreased in experimental groups I and II, and the PAC intensity between θ and high-frequency γ (hγ) decreased significantly compared to the control group. The number of days needed to meet the task criterion was more in experimental groups I and II than that of control group. The results indicate that long-term exposure to EMF could impair WM function. The possible reason may be the impaired communication between different rhythmic oscillations caused by a decrease in θ-hγ PAC intensity. This paper demonstrates the negative effects of EMF on WM and reveals the potential neural mechanisms from the changes of PAC intensity, which provides important support for further investigation of the biological effects of EMF and its mechanisms.

Electromagnetic field exposure affects the calling song, phonotaxis, and level of biogenic amines in crickets

The electromagnetic field (EMF) is ubiquitous in the environment, constituting a well-known but poorly understood stressor. Few studies have been conducted on insect responses to EMF, although they are an excellent experimental model and are of great ecological importance. In our work, we tested the effects of EMF (50 Hz, 7 mT) on the cricket Gryllus bimaculatus: the male calling song pattern, female mate choice, and levels of biogenic amines in the brain. Exposure of males to EMF increased the number and shortened the period of chips in their calling song (by 2.7% and 5% relative to the control song, respectively), but not the sound frequency. Aged (3-week-old) females were attracted to both natural and EMF-modified male signals, whereas young (1-week-old, virgin) females responded only to the modified signal, suggesting its higher attractance. Stress response of males to EMF may be responsible for the change in the calling song, as suggested by the changes in the amine levels in their brains: an increase in dopamine (by 50% relative to the control value), tyramine (65%), and serotonin (25%) concentration and a decrease in octopamine level (by 25%). These findings indicate that G. bimaculatus responds to EMF, like stressful conditions, which may change the condition and fitness of exposed individuals, disrupt mate selection, and, in consequence, affect the species' existence.

Extremely Low-Frequency Magnetic Field as a Stress Factor-Really Detrimental?-Insight into Literature from the Last Decade

Biological effects of extremely low-frequency magnetic field (ELF-MF) and its consequences on human health have become the subject of important and recurrent public debate. ELF-MF evokes cell/organism responses that are characteristic to a general stress reaction, thus it can be regarded as a stress factor. Exposure to ELF-MF "turns on" different intracellular mechanisms into both directions: compensatory or deleterious ones. ELF-MF can provoke morphological and physiological changes in stress-related systems, mainly nervous, hormonal, and immunological ones. This review summarizes the ELF-MF-mediated changes at various levels of the organism organization. Special attention is placed on the review of literature from the last decade. Most studies on ELF-MF effects concentrate on its negative influence, e.g., impairment of behavior towards depressive and anxiety disorders; however, in the last decade there was an increase in the number of research studies showing stimulating impact of ELF-MF on neuroplasticity and neurorehabilitation. In the face of numerous studies on the ELF-MF action, it is necessary to systematize the knowledge for a better understanding of the phenomenon, in order to reduce the risk associated with the exposure to this factor and to recognize the possibility of using it as a therapeutic agent.

The effects of extremely low-frequency pulsed electromagnetic fields on analgesia in the nitric oxide pathway

There is growing interest in the effects of extremely low-frequency electromagnetic fields on mechanisms in biological organisms. This study's goal is to determine the role of the Nitiric Oxide (NO) pathway for thermal pain by intentionally interfering with it using a pulsed electromagnetic field generated by an extremely low-frequency alternating current (ELF-PEMF) in combination with BAY41-2272 (sGC activator), NOS inhibitor l-NAME, and NO donor l-arginine. This study included 72 adult male Wistar albino rats (mean weight of 230 ± 12 g). The rats were kept at room temperature (22 ± 2 °C) in a 12-h light/dark cycle and in a room with sound insulation. PEMF (50 Hz, 5 mT) were applied four times a day for 30 min and at 15-min intervals for 15 days. Analgesic effects were assessed with tail-flick and hot-plate tests. Before the tests, NO donor l-arginine (300 mg/kg), sGC activator BAY41-2272 (10 mg/kg), and NOS inhibitor l-name (40 mg/kg) were injected intraperitoneally into rats in six randomly-selected groups. The maximum analgesic effect of a 5 mT electromagnetic field was on day 7. PEMF significantly increased the analgesia effect when the functioning of the NO pathway was ensured with l-arginine, which is a NO donor, and BAY41-2271, which is the intracellular receptor and sGC activator. However, there was no difference between rats treated with PEMF and the NOS inhibitor l-NAME as compared to rats only treated with PEMF. In conclusion, PEMF generate analgesia by activating the NO pain pathway.

Benign Effect of Extremely Low-Frequency Electromagnetic Field on Brain Plasticity Assessed by Nitric Oxide Metabolism during Poststroke Rehabilitation

Nitric oxide (NO) is one of the most important signal molecules, involved in both physiological and pathological processes. As a neurotransmitter in the central nervous system, NO regulates cerebral blood flow, neurogenesis, and synaptic plasticity. The aim of our study was to investigate the effect of the extremely low-frequency electromagnetic field (ELF-EMF) on generation and metabolism of NO, as a neurotransmitter, in the rehabilitation of poststroke patients. Forty-eight patients were divided into two groups: ELF-EMF and non-ELF-EMF. Both groups underwent the same 4-week rehabilitation program. Additionally, the ELF-EMF group was exposed to an extremely low-frequency electromagnetic field of 40 Hz, 7 mT, for 15 min/day. Levels of 3-nitrotyrosine, nitrate/nitrite, and TNFα in plasma samples were measured, and NOS2 expression was determined in whole blood samples. Functional status was evaluated before and after a series of treatments, using the Activity Daily Living, Geriatric Depression Scale, and Mini-Mental State Examination. We observed that application of ELF-EMF significantly increased 3-nitrotyrosine and nitrate/nitrite levels, while expression of NOS2 was insignificantly decreased in both groups. The results also show that ELF-EMF treatments improved functional and mental status. We conclude that ELF-EMF therapy is capable of promoting recovery in poststroke patients.

Effects of Phenobarbital on Expression of UDP-Glucuronosyltransferase 1a6 and 1a7 in Rat Brain

UDP-glucuronosyltransferase (UGT), a phase II drug-metabolizing enzyme, is expressed in the brain and can catalyze glucuronidation of endogenous and exogenous substrates in the brain. Thus, changes in UGT1A expression could affect homeostasis and drug efficacy. Phenobarbital (PB), a typical inducer of drug-metabolizing enzymes, has been reported to induce oxidative stress and epigenetic changes, which could alter UGT expression in the brain. Here, we aimed to clarify the effects of PB on Ugt1a6 and Ugt1a7 gene expression in rat brains. Sprague-Dawley rats were treated intraperitoneally with PB (80 mg/kg), once daily for 7 days. Ugt1a6 and Ugt1a7 mRNA expression levels were increased in the striatum and thalamus (Ugt1a6, 3.0- and 2.9-fold, respectively; Ugt1a7, 2.6- and 2.6-fold, respectively). Acetaminophen glucuronidation was also increased in the medulla oblongata and thalamus by 1.8- and 1.2-fold, respectively. The induction rates within different brain regions were correlated with Ugt1a6 and Ugt1a7 mRNA expression, and the degree of induction also correlated with that of NF-E2-related factor-2 mRNA. Measurement of oxidative stress markers suggested that PB induced oxidative stress in brain regions in which Ugt1a6 and Ugt1a7 mRNAs were increased. Moreover, histone modifications were altered by PB treatment, resulting in increased histone H3 lysine 4 trimethylation in the striatum and thalamus and decreased histone H3 lysine 9 trimethylation in the thalamus. These results suggested that oxidative stress and histone modifications may promote transcriptional activation of Ugt1a6 and Ugt1a7 genes. In summary, Ugt1a6 and Ugt1a7 mRNA levels were increased by PB treatment, which may alter pharmacokinetics in the brain.

Low intensity magnetic field influences short-term memory: A study in a group of healthy students

This study analyzes if an external magnetic stimulus (2 kHz and approximately 0.1 μT applied near frontal cortex) influences working memory, perception, binary decision, motor execution, and sustained attention in humans. A magnetic stimulus and a sham stimulus were applied to both sides of the head (frontal cortex close to temporal-parietal area) in young and healthy male test subjects (n = 65) while performing Sternberg's memory scanning task. There was a significant change in reaction time. Times recorded for perception, sustained attention, and motor execution were lower in exposed subjects (P < 0.01). However, time employed in binary decision increased for subjects exposed to magnetic fields. From results, it seems that a low intensity 2 kHz exposure modifies short-term working memory, as well as perception, binary decision, motor execution, and sustained attention.