A Single Exposure to GSM-1800 MHz Signals in the Course of an Acute Neuroinflammatory Reaction can Alter Neuronal Responses and Microglial Morphology in the Rat Primary Auditory Cortex.

Neuroscience · 2018 · Mixed · Low evidence

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MixedLow evidencePaper 5529

Study snapshot

PublicationNeuroscience · 2018

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

During mobile phone conversations, the temporal lobe neural networks involved in processing auditory information are exposed to electromagnetic fields (EMF) such as pulse-modulated GSM-1800 MHz radiofrequencies that convey wireless communications. The effects of these EMF on the brain affected by a pathological condition remain little investigated. In this study, rats injected with lipopolysaccharide (LPS) to induce neuroinflammation were exposed "head-only" to GSM-1800 MHz signals for two hours at a specific absorption rate (SAR) that reached an average value of 1.55 W/kg in the auditory cortex (ACx). Immunodetection of Iba1, a microglial marker, and electrophysiological recordings in the ACx three to six hours after global system for communication (GSM) exposure, or sham-exposure, showed that exposure to GSM-1800 MHz resulted in a growth of microglial processes and a reduction in spontaneous firing rate. More importantly, there was a significant reduction in evoked responses to artificial and natural stimuli and an increase in response duration. The response latency and the bandwidth of the frequency tuning were unchanged, but the GSM exposure led to a higher proportion of cortical sites exhibiting abnormally high acoustic thresholds. These modifications were not observed in rats exposed to GSM-1800 MHz without pretreatment with LPS. Together our data provide evidence that in neuroinflammatory conditions, acute exposure to GSM-1800 MHz can significantly affect microglia and neuronal activity underling auditory perception.

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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 directionmixed

PopulationRats with LPS-induced neuroinflammation; comparison groups included sham-exposed and non-LPS-pretreated rats

Sample sizeNot supplied

ExposureRF · 1800 MHz · 1.55 W/kg · 2 hours (single head-only exposure)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In LPS-pretreated rats, a single 2-hour head-only exposure to GSM-1800 MHz (average SAR 1.55 W/kg in auditory cortex) was associated with growth of microglial processes, reduced spontaneous firing rate, reduced evoked responses, and increased response duration measured 3–6 hours post-exposure. Response latency and frequency tuning bandwidth were unchanged, but a higher proportion of cortical sites showed abnormally high acoustic thresholds. These modifications were not observed in rats exposed to GSM-1800 MHz without LPS pretreatment.

Outcomes measured

Microglial morphology (Iba1 immunodetection)
Auditory cortex electrophysiology: spontaneous firing rate
Evoked responses to artificial and natural auditory stimuli
Response duration
Response latency
Frequency tuning bandwidth
Acoustic thresholds (proportion of sites with abnormally high thresholds)

Limitations

Sample size not reported in provided abstract/metadata
Short follow-up window (3–6 hours post-exposure)
Animal model with induced neuroinflammation (LPS) may limit generalizability to humans
Single acute exposure only

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 1800,
    "sar_wkg": 1.55,
    "duration": "2 hours (single head-only exposure)"
  },
  "population": "Rats with LPS-induced neuroinflammation; comparison groups included sham-exposed and non-LPS-pretreated rats",
  "sample_size": null,
  "outcomes": [
    "Microglial morphology (Iba1 immunodetection)",
    "Auditory cortex electrophysiology: spontaneous firing rate",
    "Evoked responses to artificial and natural auditory stimuli",
    "Response duration",
    "Response latency",
    "Frequency tuning bandwidth",
    "Acoustic thresholds (proportion of sites with abnormally high thresholds)"
  ],
  "main_findings": "In LPS-pretreated rats, a single 2-hour head-only exposure to GSM-1800 MHz (average SAR 1.55 W/kg in auditory cortex) was associated with growth of microglial processes, reduced spontaneous firing rate, reduced evoked responses, and increased response duration measured 3–6 hours post-exposure. Response latency and frequency tuning bandwidth were unchanged, but a higher proportion of cortical sites showed abnormally high acoustic thresholds. These modifications were not observed in rats exposed to GSM-1800 MHz without LPS pretreatment.",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not reported in provided abstract/metadata",
    "Short follow-up window (3–6 hours post-exposure)",
    "Animal model with induced neuroinflammation (LPS) may limit generalizability to humans",
    "Single acute exposure only"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "GSM-1800",
    "1800 MHz",
    "radiofrequency",
    "RF-EMF",
    "head-only exposure",
    "specific absorption rate",
    "SAR",
    "auditory cortex",
    "neuroinflammation",
    "lipopolysaccharide",
    "LPS",
    "microglia",
    "Iba1",
    "electrophysiology",
    "neuronal firing",
    "auditory perception"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.25,
      "reason": "Study evaluates RF exposure with SAR metric relevant to exposure guidelines."
    }
  ]
}

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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.neuroscience.2018.06.002
PubMed: 29902504

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A Single Exposure to GSM-1800 MHz Signals in the Course of an Acute Neuroinflammatory Reaction can Alter Neuronal Responses and Microglial Morphology in the Rat Primary Auditory Cortex.