Effect of chronic intermittent exposure to AM radiofrequency field on responses to various types of noxious stimuli in growing rats.

Electromagnetic biology and medicine · 2008 · Mixed · Low evidence

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MixedLow evidencePaper 4996

In rats exposed to 73.5 MHz amplitude-modulated RF for 45 days (2 h/day), TFL was not affected and thresholds for TF and VD were not affected. HPL was decreased (p<0.01) and VA threshold was significantly decreased (p<0.01). Tonic pain rating was decreased (p…

Study snapshot

PublicationElectromagnetic biology and medicine · 2008

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

There are several reports of altered pain sensation after exposure (from a few minutes to hours in single or repeated doses for 2-3 weeks) to electromagnetic fields (EMF) in adults. The commonly utilized noxious stimulus is radiant heat. The nociceptive responses are known to be influenced by characteristics of stimulus, organism, and environment. We studied the pattern of nociceptive responses to various noxious stimuli in growing rats exposed to radiofrequency field (73.5 MHz amplitude modulated, 16 Hz power density 1.33 mw/cm(2), SAR = 0.4 w/kg) for 45 d (2 h/d). Threshold current for stimulation of nociceptive afferents to mediate motor response of tail (TF), vocalization during stimulus (VD), and vocalization after discharge (VA); the withdrawal latency of tail (TFL) and hind paw (HPL) to thermal noxious stimulus and tonic pain responses were recorded in every rat. The TFL was not affected, HPL was decreased (p < 0.01), and the thresholds of TF and VD were not affected, while, that of VA was significantly decreased. The tonic pain rating was decreased (p < 0.01). A decrease in the threshold of VA (p < 0.01) is indicative of an increase in the emotional component of the response to the phasic pain, whereas a decrease in the pain rating indicates analgesia in response to the tonic pain. The results of our study suggest that chronic (45 d), intermittent (2 h/d) amplitude modulated RF field exposure to the peripubertal rat increases the emotional component of phasic pain over a basal eaualgesic state, while late response to tonic pain is decreased. The data suggest that amplitude modulated RF field differentially affects the mechanisms involved in the processing of various noxious stimuli.

Machine Enhanced Logic

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 directionmixed

PopulationGrowing/peripubertal rats

Sample sizeNot supplied

ExposureRF · 73.5 MHz · 0.4 W/kg · 45 d (2 h/d); amplitude modulated (16 Hz); power density 1.33 mW/cm^2

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Outcomes measured

Tail-flick withdrawal latency (TFL) to thermal stimulus
Hind paw withdrawal latency (HPL) to thermal stimulus
Threshold current for tail motor response (TF)
Vocalization during stimulus threshold (VD)
Vocalization after discharge threshold (VA)
Tonic pain rating

Limitations

Sample size not reported in the abstract
Details of randomization/blinding not reported in the abstract
Exposure source/setup not described in the abstract beyond frequency/modulation/power density/SAR
Statistical details beyond p-values not provided in the abstract

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "RF",
    "source": null,
    "frequency_mhz": 73.5,
    "sar_wkg": 0.4,
    "duration": "45 d (2 h/d); amplitude modulated (16 Hz); power density 1.33 mW/cm^2"
  },
  "population": "Growing/peripubertal rats",
  "sample_size": null,
  "outcomes": [
    "Tail-flick withdrawal latency (TFL) to thermal stimulus",
    "Hind paw withdrawal latency (HPL) to thermal stimulus",
    "Threshold current for tail motor response (TF)",
    "Vocalization during stimulus threshold (VD)",
    "Vocalization after discharge threshold (VA)",
    "Tonic pain rating"
  ],
  "main_findings": "In rats exposed to 73.5 MHz amplitude-modulated RF for 45 days (2 h/day), TFL was not affected and thresholds for TF and VD were not affected. HPL was decreased (p<0.01) and VA threshold was significantly decreased (p<0.01). Tonic pain rating was decreased (p<0.01).",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not reported in the abstract",
    "Details of randomization/blinding not reported in the abstract",
    "Exposure source/setup not described in the abstract beyond frequency/modulation/power density/SAR",
    "Statistical details beyond p-values not provided in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency",
    "AM radiofrequency",
    "73.5 MHz",
    "amplitude modulated",
    "16 Hz",
    "SAR 0.4 W/kg",
    "power density 1.33 mW/cm^2",
    "rats",
    "peripubertal",
    "nociception",
    "pain",
    "tail-flick",
    "hind paw latency",
    "vocalization",
    "tonic pain"
  ],
  "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: 10.1080/15368370802304155
PubMed: 18821202

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