Chronic Nonmodulated Microwave Radiations in Mice Produce Anxiety-like and Depression-like Behaviours and Calcium- and NO-related Biochemical Changes in the Brain

Effects of Nonthermal Radiofrequency Stimulation on Neuronal Activity and Neural Circuit in Mice

Whether the nonthermal effects of radiofrequency radiation (RFR) exist and how nonthermal RFR acts on the nervous system are unknown. An animal model of spatial memory impairment is established by exposing mice to 2856-MHz RFR in the range of thermal noise (≤1 °C). Glutamate release in the dorsal hippocampus (dHPC) CA1 region is not significantly changed after radiofrequency exposure, whereas dopamine release is reduced. Importantly, RFR enhances glutamatergic CA1 pyramidal neuron calcium activity by nonthermal mechanisms, which recover to the basal level with RFR termination. Furthermore, suppressed dHPC dopamine release induced by radiofrequency exposure is due to decreased density of dopaminergic projections from the locus coeruleus to dHPC, and artificial activation of dopamine axon terminals or D1 receptors in dHPC CA1 improve memory damage in mice exposed to RFR. These findings indicate that nonthermal radiofrequency stimulation modulates ongoing neuronal activity and affects nervous system function at the neural circuit level.

Changes in cognitive function, synaptic structure and protein expression after long-term exposure to 2.856 and 9.375 GHz microwaves

Health hazards from long-term exposure to microwaves, especially the potential for changes in cognitive function, are attracting increasing attention. The purpose of this study was to explore changes in spatial learning and memory and synaptic structure and to identify differentially expressed proteins in hippocampal and serum exosomes after long-term exposure to 2.856 and 9.375 GHz microwaves. The spatial reference learning and memory abilities and the structure of the DG area were impaired after long-term exposure to 2.856 and 9.375 GHz microwaves. We also found a decrease in SNARE-associated protein Snapin and an increase in charged multivesicular body protein 3 in the hippocampus, indicating that synaptic vesicle recycling was inhibited and consistent with the large increase in presynaptic vesicles. Moreover, we investigated changes in serum exosomes after 2.856 and 9.375 GHz microwave exposure. The results showed that long-term 2.856 GHz microwave exposure could induce a decrease in calcineurin subunit B type 1 and cytochrome b-245 heavy chain in serum exosomes. While the 9.375 GHz long-term microwave exposure induced a decrease in proteins (synaptophysin-like 1, ankyrin repeat and rabankyrin-5, protein phosphatase 3 catalytic subunit alpha and sodium-dependent phosphate transporter 1) in serum exosomes. In summary, long-term microwave exposure could lead to different degrees of spatial learning and memory impairment, EEG disturbance, structural damage to the hippocampus, and differential expression of hippocampal tissue and serum exosomes.

The Role of NMDAR and BDNF in Cognitive Dysfunction Induced by Different Microwave Radiation Conditions in Rats

Background: To investigate the effects of different levels of microwave radiation on learning and memory in Wistar rats and explore the underlying mechanisms of N-methyl-D-aspartate receptor (NMDAR/NR) and Brain-derived neurotropic factor (BDNF); Methods: A total of 140 Wistar rats were exposed to microwave radiation levels of 0, 10, 30 or 50 mW/cm2 for 6 min. Morris Water Maze Test, high-performance liquid chromatography, Transmission Electron Microscope and Western blotting were used; Results: The 30 and 50 mW/cm2 groups exhibited longer average escape latencies and fewer platform crossings than the 0 mW/cm2 group from 6 h to 3 d after microwave radiation. Alterations in the amino acid neurotransmitters of the hippocampi were shown at 6 h, 3 d and 7 d after exposure to 10, 30 or 50 mW/cm2 microwave radiation. The length and width of the Postsynaptic density were increased. The expression of NR1, NR2A and NR2B increased from day 1 to day 7; Postsynaptic density protein-95 and cortactin expression increased from day 3 to day 7; BDNF and Tyrosine kinase receptor B (TrkB) expression increased between 6 h and 1 d after 30 mW/cm2 microwave radiation exposure, but they decreased after 50mW/cm2 exposure. Conclusions: Microwave exposure (30 or 50 mW/cm2, for 6 min) may cause abnormalities in neurotransmitter release and synaptic structures, resulting in impaired learning and memory; BDNF and NMDAR-related signaling molecules might contribute differently to these alterations.

Effects of Radiofrequency Electromagnetic Radiation on Neurotransmitters in the Brain

With the rapid development of electronic information in the past 30 years, technical achievements based on electromagnetism have been widely used in various fields pertaining to human production and life. Consequently, electromagnetic radiation (EMR) has become a substantial new pollution source in modern civilization. The biological effects of EMR have attracted considerable attention worldwide. The possible interaction of EMR with human organs, especially the brain, is currently where the most attention is focused. Many studies have shown that the nervous system is an important target organ system sensitive to EMR. In recent years, an increasing number of studies have focused on the neurobiological effects of EMR, including the metabolism and transport of neurotransmitters. As messengers of synaptic transmission, neurotransmitters play critical roles in cognitive and emotional behavior. Here, the effects of EMR on the metabolism and receptors of neurotransmitters in the brain are summarized.

Association Between Mobile Phone Radiation Exposure and the Secretion of Melatonin and Cortisol, Two Markers of the Circadian System: A Review

The extremely important use of mobile phones in the world, at all ages of life, including children and adolescents, leads to significant exposure of these populations to electromagnetic waves of radiofrequency. The question, therefore, arises as to whether exposure to these radiofrequencies (RFs) could lead to deleterious effects on the body's biological systems and health. In the current article, we review the effects, in laboratory animals and humans, of exposure to RF on two hormones considered as endocrine markers: melatonin, a neurohormone produced by the pineal gland and cortisol, a glucocorticosteroid synthesized by the adrenal glands. These two hormones are also considered as markers of the circadian system. The literature search was performed using PubMed, Medline, Web of Sciences (ISI Web of Knowledge), Google Scholar, and EMF Portal. From this review on RF effects on cortisol and melatonin, it appears that scientific papers in the literature are conflicting, showing effects, no effects, or inconclusive data. This implies the need for additional research on higher numbers of subjects and with protocols perfectly controlled with follow-up studies to better determine whether the chronic effect of RF on the biological functioning and health of users exists (or not). Bioelectromagnetics. 2021;42:5-17. © 2020 Bioelectromagnetics Society.

2.45 GHz microwave radiation impairs learning, memory, and hippocampal synaptic plasticity in the rat

Microwave (MW) radiation has a close relationship with neurobehavioral disorders. Due to the widespread usage of MW radiation, especially in our homes, it is essential to investigate the direct effect of MW radiation on the central nervous system. Therefore, this study was carried out to determine the effect of MW radiation on memory and hippocampal synaptic plasticity. The rats were exposed to 2.45 GHz MW radiation (continuous wave with overall average power density of 0.016 mW/cm2 and overall average whole-body specific absorption rate value of 0.017 W/kg) for 2 h/day over a period of 40 days. Spatial learning and memory were tested by radial maze and passive avoidance tests. We evaluated the synaptic plasticity and hippocampal neuronal cells number by field potential recording and Giemsa staining, respectively. Our results showed that MW radiation exposure decreased the learning and memory performance that was associated with decrement of long-term potentiation induction and excitability of CA1 neurons. However, MW radiation did not have any effects on short-term plasticity and paired-pulse ratio as a good indirect index for measurement of glutamate release probability. The evaluation of hippocampal morphology indicated that the neuronal density in the hippocampal CA1 area was significantly decreased by MW.

Effects of 1.8 GHz Radiofrequency Fields on the Emotional Behavior and Spatial Memory of Adolescent Mice

The increasing use of mobile phones by teenagers has raised concern about the cognitive effects of radiofrequency (RF) fields. In this study, we investigated the effects of 4-week exposure to a 1.8 GHz RF field on the emotional behavior and spatial memory of adolescent male mice. Anxiety-like behavior was evaluated by open field test (OFT) and elevated plus maze (EPM) test, while depression-like behavior was evaluated by sucrose preference test (SPT), tail suspension test (TST) and forced swim test (FST). The spatial learning and memory ability were evaluated by Morris water maze (MWM) experiments. The levels of amino acid neurotransmitters were determined by liquid chromatography-mass spectrometry (LC-MS). The histology of the brain was examined by hematoxylin-eosin (HE) staining. It was found that the depression-like behavior, spatial memory ability and histology of the brain did not change obviously after RF exposure. However, the anxiety-like behavior increased in mice, while, the levels of γ-aminobutyric acid (GABA) and aspartic acid (Asp) in cortex and hippocampus significantly decreased after RF exposure. These data suggested that RF exposure under these conditions do not affect the depression-like behavior, spatial memory and brain histology in adolescent male mice, but it may however increase the level of anxiety, and GABA and Asp were probably involved in this effect.

Recent advances in the effects of microwave radiation on brains

This study concerns the effects of microwave on health because they pervade diverse fields of our lives. The brain has been recognized as one of the organs that is most vulnerable to microwave radiation. Therefore, in this article, we reviewed recent studies that have explored the effects of microwave radiation on the brain, especially the hippocampus, including analyses of epidemiology, morphology, electroencephalograms, learning and memory abilities and the mechanisms underlying brain dysfunction. However, the problem with these studies is that different parameters, such as the frequency, modulation, and power density of the radiation and the irradiation time, were used to evaluate microwave radiation between studies. As a result, the existing data exhibit poor reproducibility and comparability. To determine the specific dose-effect relationship between microwave radiation and its biological effects, more intensive studies must be performed.