The extremely low-frequency electromagnetic field (50 Hz) can establish a new "set-point" for the activity of the locus coeruleus-noradrenergic (LC-NA) system in rat.

Brain research bulletin · 2024 · Mixed · Low evidence

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MixedLow evidencePaper 5820

Study snapshot

PublicationBrain research bulletin · 2024

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

Exposure of organisms to extremely low-frequency electromagnetic field (ELF-EMF; 50 Hz) has been increasing in recent decades, which is connected with dynamic technological development. ELF-EMF is considered a stress factor and its effects on organisms are still being investigated. We aimed to determine its impact on the locus coeruleus-noradrenergic (LC-NA) system enabling adaptation to stressful conditions. For this purpose, we exposed rats to 50 Hz ELF-EMF of 1 and 7 mT, 1 h/day for 7 days. The procedure was repeated three times to examine the organism's adaptive capabilities. Subsequently, the concentration of adrenaline, noradrenaline and its metabolite MHPG as well as the expression of the β2-adrenergic receptor was assessed. After the end of each exposure, part of the animals were subjected to a behavioural test to assess the influence of repeated ELF-EMF exposure on stress response to subsequent stress factors. Our research proved that mechanisms underlying the effects of ELF-EMF on stress response include the LC-NA system. ELF-EMF of 1 mT induced adaptive changes in the NA-LC system. However, exposure to 7 mT caused increased activity of the stress system which resulted in sensitization to subsequent, heterotypic (different from the one previously acting) stress factor. As ELF-EMF of 7 mT caused a profound decrease in β2-AR level would strongly inhibit the potential for neuroplastic processes in the hippocampus. Moreover, rats exposed to ELF-EMF of 7 mT showed moderately increased anxiety-related behaviour. Disturbances in NA-LC transmission may underlie the development of some neurodegenerative and psychiatric diseases which indicates the possible involvement of ELF-EMF in the pathogenesis of these disorders.

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Study typeanimal

Effect directionmixed

PopulationRats

Sample sizeNot supplied

ExposureELF · 0.05 MHz · 1 h/day for 7 days; procedure repeated three times

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Rats were exposed to 50 Hz ELF-EMF at 1 mT or 7 mT (1 h/day for 7 days; repeated three times). The authors report that 1 mT induced adaptive changes in the LC-NA system, whereas 7 mT increased activity of the stress system, produced sensitization to a subsequent heterotypic stressor, decreased β2-adrenergic receptor levels, and was associated with moderately increased anxiety-related behavior.

Outcomes measured

Adrenaline concentration
Noradrenaline concentration
MHPG (noradrenaline metabolite) concentration
β2-adrenergic receptor expression
Behavioral stress response
Anxiety-related behavior

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": "1 h/day for 7 days; procedure repeated three times"
  },
  "population": "Rats",
  "sample_size": null,
  "outcomes": [
    "Adrenaline concentration",
    "Noradrenaline concentration",
    "MHPG (noradrenaline metabolite) concentration",
    "β2-adrenergic receptor expression",
    "Behavioral stress response",
    "Anxiety-related behavior"
  ],
  "main_findings": "Rats were exposed to 50 Hz ELF-EMF at 1 mT or 7 mT (1 h/day for 7 days; repeated three times). The authors report that 1 mT induced adaptive changes in the LC-NA system, whereas 7 mT increased activity of the stress system, produced sensitization to a subsequent heterotypic stressor, decreased β2-adrenergic receptor levels, and was associated with moderately increased anxiety-related behavior.",
  "effect_direction": "mixed",
  "limitations": [],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF-EMF",
    "50 Hz",
    "1 mT",
    "7 mT",
    "locus coeruleus",
    "noradrenergic system",
    "stress response",
    "adrenaline",
    "noradrenaline",
    "MHPG",
    "β2-adrenergic receptor",
    "anxiety"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.25,
      "reason": "Study examines biological effects of 50 Hz ELF exposure, which is relevant to some occupational ELF contexts, though no specific source is stated."
    }
  ]
}

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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: 10.1016/j.brainresbull.2024.111111
PubMed: 39486464

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The extremely low-frequency electromagnetic field (50 Hz) can establish a new "set-point" for the activity of the locus coeruleus-noradrenergic (LC-NA) system in rat.