Millimeter Wave Radiation Activates Leech Nociceptors via TRPV1-Like Receptor Sensitization

2019 · Harm · Low evidence

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HarmLow evidencePaper 1814

Study snapshot

Publicationmanual · 2019

Study typeanimal

Reported directionHarm

Evidence ratingLow

Abstract

Millimeter Wave Radiation Activates Leech Nociceptors via TRPV1-Like Receptor Sensitization Romanenko S, Harvey AR, Hool L, Fan S, Wallace VP. Millimeter Wave Radiation Activates Leech Nociceptors via TRPV1-Like Receptor Sensitization. Biophys J. 2019 Apr 25. pii: S0006-3495(19)30340-6. doi: 10.1016/j.bpj.2019.04.021. Abstract There is evidence that millimeter waves (MMWs) can have an impact on cellular function, including neurons. Earlier in vitro studies have shown that exposure levels well below the recommended safe limit of 1 mW/cm2 cause changes in the action potential (AP) firing rate, resting potential, and AP pulse shape of sensory neurons in leech preparations as well as alter neuronal properties in rat cortical brain slices; these effects differ from changes induced by direct heating. In this article, we compare the responses of thermosensitive primary nociceptors of the medicinal leech under thermal heating and MMW irradiation (80-170 mW/cm2 at 60 GHz). The results show that MMW exposure causes an almost twofold decrease in the threshold for activation of the AP compared with thermal heating (3.9 ± 0.4 vs. 8.3 ± 0.4 mV, respectively). Our analysis suggests that MMWs- mediated threshold alterations are not caused by the enhancement of voltage-gated sodium and potassium conductance. We propose that the reduction in AP threshold can be attributed to the sensitization of the transient receptor potential vanilloid 1-like receptor in the leech nociceptor. In silico modeling supported our experimental findings. Our results provide evidence that MMW exposure stimulates specific receptor responses that differ from direct thermal heating, fostering the need for additional studies. ncbi.nlm.nih.gov

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeanimal

Effect directionharm

PopulationThermosensitive primary nociceptors of the medicinal leech (leech preparation)

Sample sizeNot supplied

ExposuremmWave · 60000 MHz

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

In leech thermosensitive primary nociceptors, millimeter-wave irradiation (80–170 mW/cm2 at 60 GHz) produced an almost twofold decrease in the action potential activation threshold compared with thermal heating (3.9 ± 0.4 vs 8.3 ± 0.4 mV). The authors report that the threshold alteration was not explained by enhanced voltage-gated sodium and potassium conductance and propose TRPV1-like receptor sensitization, supported by in silico modeling.

Outcomes measured

Action potential (AP) activation threshold
Neuronal excitability/activation of nociceptors
Comparison of responses under thermal heating vs millimeter-wave irradiation
Mechanistic involvement of TRPV1-like receptor sensitization
Voltage-gated sodium and potassium conductance (mechanistic assessment)
In silico modeling support for experimental findings

Limitations

Sample size not reported in the abstract
Exposure duration not reported in the abstract
Findings are from a leech preparation; generalizability to humans is not established in the abstract
Mechanistic conclusion is described as a proposal; causality may not be fully established from the abstract alone

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "mmWave",
    "source": null,
    "frequency_mhz": 60000,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Thermosensitive primary nociceptors of the medicinal leech (leech preparation)",
  "sample_size": null,
  "outcomes": [
    "Action potential (AP) activation threshold",
    "Neuronal excitability/activation of nociceptors",
    "Comparison of responses under thermal heating vs millimeter-wave irradiation",
    "Mechanistic involvement of TRPV1-like receptor sensitization",
    "Voltage-gated sodium and potassium conductance (mechanistic assessment)",
    "In silico modeling support for experimental findings"
  ],
  "main_findings": "In leech thermosensitive primary nociceptors, millimeter-wave irradiation (80–170 mW/cm2 at 60 GHz) produced an almost twofold decrease in the action potential activation threshold compared with thermal heating (3.9 ± 0.4 vs 8.3 ± 0.4 mV). The authors report that the threshold alteration was not explained by enhanced voltage-gated sodium and potassium conductance and propose TRPV1-like receptor sensitization, supported by in silico modeling.",
  "effect_direction": "harm",
  "limitations": [
    "Sample size not reported in the abstract",
    "Exposure duration not reported in the abstract",
    "Findings are from a leech preparation; generalizability to humans is not established in the abstract",
    "Mechanistic conclusion is described as a proposal; causality may not be fully established from the abstract alone"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "millimeter waves",
    "mmWave",
    "60 GHz",
    "nociceptors",
    "medicinal leech",
    "sensory neurons",
    "action potential threshold",
    "TRPV1-like receptor",
    "sensitization",
    "thermal heating comparison",
    "in silico modeling"
  ],
  "suggested_hubs": [
    {
      "slug": "5g-policy",
      "weight": 0.55,
      "reason": "Uses 60 GHz millimeter-wave exposure, relevant to mmWave frequencies used in some 5G deployments."
    }
  ]
}

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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.bpj.2019.04.021
PubMed: Not supplied

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