Decreased dopamine in striatum and difficult locomotor recovery from MPTP insult after exposure to radiofrequency electromagnetic fields.

Scientific reports · 2019 · Harm · Low evidence

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HarmLow evidencePaper 5597

Study snapshot

PublicationScientific reports · 2019

Study typeanimal

Reported directionHarm

Evidence ratingLow

Abstract

Concern is growing about possible neuronal effects of human exposure to radiofrequency electromagnetic fields because of the increasing usage of cell phones and the close proximity of these devices to the brain when in use. We found that exposure to a radiofrequency electromagnetic field (RF-EMF) of 835 MHz (4.0 W/kg specific absorption rate [SAR] for 5 h/day for 12 weeks) affects striatal neurons in C57BL/6 mice. The number of synaptic vesicles (SVs) in striatal presynaptic boutons was significantly decreased after RF-EMF exposure. The expression levels of synapsin I and II were also significantly decreased in the striatum of the RF-EMF-exposed group. RF-EMF exposure led to a reduction in dopamine concentration in the striatum and also to a decrease in the expression of tyrosine hydroxylase in striatal neurons. Furthermore, in behavioral tests, exposure to RF-EMF impeded the recovery of locomotor activities after repeated treatments with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). These results suggest that the observed decrease in dopamine concentration in the striatum was caused by both a reduction in the number of dopaminergic neurons and a decline in the number of SVs. The decreased dopamine neuron numbers and concentration seen after RF-EMF exposure would have caused the difficult recovery after MPTP treatment. In summary, our results strongly suggest that exposing the brain to RF-EMF can decrease the number of SVs and dopaminergic neurons in the striatum. These primary changes impair the recovery of locomotor activities following MPTP damage to the striatum.

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AI evidence extraction

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Study typeanimal

Effect directionharm

PopulationC57BL/6 mice

Sample sizeNot supplied

ExposureRF · 835 MHz · 4 W/kg · 5 h/day for 12 weeks

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In C57BL/6 mice, RF-EMF exposure (835 MHz; SAR 4.0 W/kg; 5 h/day for 12 weeks) was associated with decreased synaptic vesicle numbers in striatal presynaptic boutons and reduced synapsin I/II expression. Exposed mice also showed reduced striatal dopamine concentration and decreased tyrosine hydroxylase expression, and RF-EMF exposure impeded recovery of locomotor activity after repeated MPTP treatments.

Outcomes measured

Striatal synaptic vesicle number in presynaptic boutons
Striatal synapsin I and II expression
Striatal dopamine concentration
Tyrosine hydroxylase expression in striatal neurons
Recovery of locomotor activity after repeated MPTP treatment

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 835,
    "sar_wkg": 4,
    "duration": "5 h/day for 12 weeks"
  },
  "population": "C57BL/6 mice",
  "sample_size": null,
  "outcomes": [
    "Striatal synaptic vesicle number in presynaptic boutons",
    "Striatal synapsin I and II expression",
    "Striatal dopamine concentration",
    "Tyrosine hydroxylase expression in striatal neurons",
    "Recovery of locomotor activity after repeated MPTP treatment"
  ],
  "main_findings": "In C57BL/6 mice, RF-EMF exposure (835 MHz; SAR 4.0 W/kg; 5 h/day for 12 weeks) was associated with decreased synaptic vesicle numbers in striatal presynaptic boutons and reduced synapsin I/II expression. Exposed mice also showed reduced striatal dopamine concentration and decreased tyrosine hydroxylase expression, and RF-EMF exposure impeded recovery of locomotor activity after repeated MPTP treatments.",
  "effect_direction": "harm",
  "limitations": [],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency electromagnetic fields",
    "RF-EMF",
    "835 MHz",
    "specific absorption rate",
    "SAR",
    "striatal neurons",
    "synaptic vesicles",
    "synapsin",
    "dopamine",
    "tyrosine hydroxylase",
    "MPTP",
    "locomotor recovery",
    "C57BL/6 mice"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1038/s41598-018-37874-z
PubMed: 30718744

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