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.

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.

AI evidence extraction

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

Suggested hubs

• occupational-exposure (0.25)
  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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    "exposure": {
        "band": "ELF",
        "source": null,
        "frequency_mhz": 0.05000000000000000277555756156289135105907917022705078125,
        "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": 0.7399999999999999911182158029987476766109466552734375,
    "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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