Alterations of cognitive function and 5-HT system in rats after long term microwave exposure
Physiol Behav. 2014 Dec 24. pii: S0031-9384(14)00663-5. doi: 10.1016/j.physbeh.2014.12.039. [Epub ahead of print]
Li H1, Peng R1, Wang C1, Qiao S1, Yong-Zou1, Gao Y1, Xu X1, Wang S1, Dong J1, Zuo H1, Li-Zhao1, Zhou H2, Wang L3, Hu X4.
Author information
Abstract
The increased use of microwaves raises concerns about its impact on health including cognitive function in which neurotransmitter system plays an important role. In this study, we focused on the serotonergic system and evaluated the long term effects of chronic microwave radiation on cognition and correlated items. Wistar rats were exposed or sham exposed to 2.856GHz microwaves with the average power density of 5, 10, 20 or 30mW/cm2respectively for 6min three times a week up to 6weeks. At different time points after the last exposure, spatial learning and memory function, morphology structure of the hippocampus, electroencephalogram (EEG) and neurotransmitter content (amino acid and monoamine) of rats were tested. Above results raised our interest in serotonin system. Tryptophan hydroxylase 1 (TPH1) and monoamine oxidase (MAO), two important rate-limiting enzymes in serotonin synthesis and metabolic process respectively, were detected. Expressions of serotonin receptors including 5-HT1A, 2A, 2C receptors were measured. We demonstrated that chronic exposure to microwave (2.856GHz, with the average power density of 5, 10, 20 and 30mW/cm2) could induce dose-dependent deficit of spatial learning and memory in rats accompanied with inhibition of brain electrical activity, the degeneration of hippocampus neurons, and the disturbance of neurotransmitters, among which the increase of 5-HT occurred as the main long-term change that the decrease of its metabolism partly contributed to. Besides, the variations of 5-HT1AR and 5-HT2CR expressions were also indicated. The results suggested that in the long-term way, chronic microwave exposure could induce cognitive deficit and 5-HT system may be involved in it.
Copyright © 2014. Published by Elsevier Inc.
http://www.ncbi.nlm.nih.gov/pubmed/25542888?dopt
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Effect of occupational EMF exposure from radar at two different frequency bands on plasma melatonin and serotonin levels
Int J Radiat Biol. 2015 Jan 7:1-39. [Epub ahead of print]
Singh S, Mani KV, Kapoor N.
Abstract
Abstract Objective: The purpose of the present study was to delineate the effect of chronic electromagnetic field (EMF) exposure from radar on plasma melatonin and serotonin levels in occupationally exposed military personnel. Subjects and Methods: 166 male military personnel participated in the study out of which only 155 joined for blood draw. They were divided into three sets viz control group (n=68), exposure group I (n=40) exposed to 8-12GHz and exposure group II (n=58) working with radar at 12.5-18GHz frequency. All the three groups were further split into two groups according to their years of service (up to 10 years and > 10 years) in order to investigate the effect of years of exposure from radar. Melatonin and serotonin levels were estimated by enzyme immunoassay in fasting blood samples collected during 0600-0700h. EMF measurements were recorded at different locations using Satimo EME Guard 'Personal Exposure Meter' and Narda 'Broad Band Field Meter'. Results: The group I exposed population registered a minor though not significant decrease in plasma melatonin concentration while the other group II exposed population registered statistically significant decline in melatonin concentration when compared with controls. Highly significant increase in plasma serotonin levels was found in exposure group II when compared to control whereas marginal non-significant rise was also registered in exposure group I in comparison to control. Exposure in terms of length of service up to 10 years did not produce any significant effect in the indoleamine levels in both the exposure groups when they were compared with their respective control groups. Whereas, length of service greater than 10 years was observed to decrease and increase respectively the melatonin and serotonin concentration significantly in exposure group II but not in exposure group I. However, correlation test did not yield any significant association between years of service and melatonin or serotonin levels respectively in both the exposure sets I and II. No significant association was observed between melatonin and serotonin levels as well. Conclusion: The study shows the EMF ability to influence plasma melatonin and serotonin concentration in radar workers, significantly in 12.5-18GHz range with service period greater than 10 years.
http://www.ncbi.nlm.nih.gov/pubmed/25565559?dopt=Abstract
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Occupational exposure to extremely low frequency magnetic fields and brain tumour risks in the INTEROCC study
Cancer Epidemiol Biomarkers Prev cebp.0102.2014; Published Online First June 16, 2014;
Michelle C. Turner et al.
Result from this study published in Cancer Epidemiology, Biomarkers and Prevention showed associations between extremely low frequency magnetic fields (ELF) exposure in the recent past and risk of glioma (the most frequent type of brain tumours in adults).
Occupational exposure to extremely low frequency magnetic fields (ELF) is a suspected risk factor for brain tumours, however the literature is inconsistent. Analyses of data from the seven countries (Australia, Canada, France, Germany, Israel, New Zealand, United Kingdom) in the INTEROCC study lead by CREAL, an ISGlobal research center, examined associations between occupational ELF exposure in different time windows of exposure and specific histologic types of brain tumours. The study included over 3,700 brain tumour cases and 5,400 control subjects. Estimates of cumulative exposure, average exposure, maximum exposure, and exposure duration based on an updated ELF job exposure matrix were calculated for the lifetime, and 1-4, 5-9, and 10+ years prior to the diagnosis/reference date.
Researchers found significant positive associations between cumulative ELF in the time window 1-4 years prior to the date of diagnosis/reference date and glioma, and weaker associations with meningioma. Michelle C. Turner, CREAL researcher of CREAL and first author of the publication, explains that “occupational ELF may play a role in the later stages (promotion and progression) of brain tumourigenesis”.
Reference:
Occupational exposure to extremely low frequency magnetic fields and brain tumour risks in the INTEROCC study. Michelle C. Turner et al. Cancer Epidemiol Biomarkers Prev cebp.0102.2014; Published Online First June 16, 2014
http://www.crealradiation.com/index.php/en/news/occupational-exposure-to-extremely-low-frequency-magnetic-fields-and-brain-tumour-risks-in-the-interocc-study
Physiol Behav. 2014 Dec 24. pii: S0031-9384(14)00663-5. doi: 10.1016/j.physbeh.2014.12.039. [Epub ahead of print]
Li H1, Peng R1, Wang C1, Qiao S1, Yong-Zou1, Gao Y1, Xu X1, Wang S1, Dong J1, Zuo H1, Li-Zhao1, Zhou H2, Wang L3, Hu X4.
Author information
Abstract
The increased use of microwaves raises concerns about its impact on health including cognitive function in which neurotransmitter system plays an important role. In this study, we focused on the serotonergic system and evaluated the long term effects of chronic microwave radiation on cognition and correlated items. Wistar rats were exposed or sham exposed to 2.856GHz microwaves with the average power density of 5, 10, 20 or 30mW/cm2respectively for 6min three times a week up to 6weeks. At different time points after the last exposure, spatial learning and memory function, morphology structure of the hippocampus, electroencephalogram (EEG) and neurotransmitter content (amino acid and monoamine) of rats were tested. Above results raised our interest in serotonin system. Tryptophan hydroxylase 1 (TPH1) and monoamine oxidase (MAO), two important rate-limiting enzymes in serotonin synthesis and metabolic process respectively, were detected. Expressions of serotonin receptors including 5-HT1A, 2A, 2C receptors were measured. We demonstrated that chronic exposure to microwave (2.856GHz, with the average power density of 5, 10, 20 and 30mW/cm2) could induce dose-dependent deficit of spatial learning and memory in rats accompanied with inhibition of brain electrical activity, the degeneration of hippocampus neurons, and the disturbance of neurotransmitters, among which the increase of 5-HT occurred as the main long-term change that the decrease of its metabolism partly contributed to. Besides, the variations of 5-HT1AR and 5-HT2CR expressions were also indicated. The results suggested that in the long-term way, chronic microwave exposure could induce cognitive deficit and 5-HT system may be involved in it.
Copyright © 2014. Published by Elsevier Inc.
http://www.ncbi.nlm.nih.gov/pubmed/25542888?dopt
******
Effect of occupational EMF exposure from radar at two different frequency bands on plasma melatonin and serotonin levels
Int J Radiat Biol. 2015 Jan 7:1-39. [Epub ahead of print]
Singh S, Mani KV, Kapoor N.
Abstract
Abstract Objective: The purpose of the present study was to delineate the effect of chronic electromagnetic field (EMF) exposure from radar on plasma melatonin and serotonin levels in occupationally exposed military personnel. Subjects and Methods: 166 male military personnel participated in the study out of which only 155 joined for blood draw. They were divided into three sets viz control group (n=68), exposure group I (n=40) exposed to 8-12GHz and exposure group II (n=58) working with radar at 12.5-18GHz frequency. All the three groups were further split into two groups according to their years of service (up to 10 years and > 10 years) in order to investigate the effect of years of exposure from radar. Melatonin and serotonin levels were estimated by enzyme immunoassay in fasting blood samples collected during 0600-0700h. EMF measurements were recorded at different locations using Satimo EME Guard 'Personal Exposure Meter' and Narda 'Broad Band Field Meter'. Results: The group I exposed population registered a minor though not significant decrease in plasma melatonin concentration while the other group II exposed population registered statistically significant decline in melatonin concentration when compared with controls. Highly significant increase in plasma serotonin levels was found in exposure group II when compared to control whereas marginal non-significant rise was also registered in exposure group I in comparison to control. Exposure in terms of length of service up to 10 years did not produce any significant effect in the indoleamine levels in both the exposure groups when they were compared with their respective control groups. Whereas, length of service greater than 10 years was observed to decrease and increase respectively the melatonin and serotonin concentration significantly in exposure group II but not in exposure group I. However, correlation test did not yield any significant association between years of service and melatonin or serotonin levels respectively in both the exposure sets I and II. No significant association was observed between melatonin and serotonin levels as well. Conclusion: The study shows the EMF ability to influence plasma melatonin and serotonin concentration in radar workers, significantly in 12.5-18GHz range with service period greater than 10 years.
http://www.ncbi.nlm.nih.gov/pubmed/25565559?dopt=Abstract
******
Occupational exposure to extremely low frequency magnetic fields and brain tumour risks in the INTEROCC study
Cancer Epidemiol Biomarkers Prev cebp.0102.2014; Published Online First June 16, 2014;
Michelle C. Turner et al.
Result from this study published in Cancer Epidemiology, Biomarkers and Prevention showed associations between extremely low frequency magnetic fields (ELF) exposure in the recent past and risk of glioma (the most frequent type of brain tumours in adults).
Occupational exposure to extremely low frequency magnetic fields (ELF) is a suspected risk factor for brain tumours, however the literature is inconsistent. Analyses of data from the seven countries (Australia, Canada, France, Germany, Israel, New Zealand, United Kingdom) in the INTEROCC study lead by CREAL, an ISGlobal research center, examined associations between occupational ELF exposure in different time windows of exposure and specific histologic types of brain tumours. The study included over 3,700 brain tumour cases and 5,400 control subjects. Estimates of cumulative exposure, average exposure, maximum exposure, and exposure duration based on an updated ELF job exposure matrix were calculated for the lifetime, and 1-4, 5-9, and 10+ years prior to the diagnosis/reference date.
Researchers found significant positive associations between cumulative ELF in the time window 1-4 years prior to the date of diagnosis/reference date and glioma, and weaker associations with meningioma. Michelle C. Turner, CREAL researcher of CREAL and first author of the publication, explains that “occupational ELF may play a role in the later stages (promotion and progression) of brain tumourigenesis”.
Reference:
Occupational exposure to extremely low frequency magnetic fields and brain tumour risks in the INTEROCC study. Michelle C. Turner et al. Cancer Epidemiol Biomarkers Prev cebp.0102.2014; Published Online First June 16, 2014
http://www.crealradiation.com/index.php/en/news/occupational-exposure-to-extremely-low-frequency-magnetic-fields-and-brain-tumour-risks-in-the-interocc-study