2.1 GHz electromagnetic field does not change contractility and intracellular Ca2+ transients but decreases β-adrenergic responsiveness through nitric oxide signaling in rat ventricular myocytes.

International journal of radiation biology · 2015 · Mixed · Low evidence

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MixedLow evidencePaper 4766

In rats exposed to 2.1 GHz EMF for 2 h/day for 10 weeks, fractional shortening and matched Ca2+ transient amplitude were not changed versus sham. Basal ICaL density was similar between groups, but the isoproterenol-induced ICaL response was reduced in exposed…

Study snapshot

PublicationInternational journal of radiation biology · 2015

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

PURPOSE: Due to the increasing use of wireless technology in developing countries, particularly mobile phones, the influence of electromagnetic fields (EMF) on biologic systems has become the subject of an intense debate. Therefore, in this study we investigated the effect of 2.1 GHz EMF on contractility and beta-adrenergic (β-AR) responsiveness of ventricular myocytes. MATERIALS AND METHODS: Rats were randomized to the following groups: Sham rats (SHAM) and rats exposed to 2.1 GHz EMF for 2 h/day for 10 weeks (EM-10). Sarcomere shortening and Ca(2+) transients were recorded in isolated myocytes loaded with Fura2-AM and electrically stimulated at 1 Hz, while L-type Ca(2+) currents (I(CaL)) were measured using whole-cell patch clamping at 36 ± 1°C. Cardiac nitric oxide (NO) levels were measured in tissue samples using a colorimetric assay kit. RESULTS: Fractional shortening and amplitude of the matched Ca(2+) transients were not changed in EM-10 rats. Although the isoproterenol-induced (10(-6) M) I(CaL) response was reduced in rats exposed to EMF, basal I(CaL) density in myocytes was similar between the two groups (p < 0.01). Moreover, EMF exposure led to a significant increase in nitric oxide levels in rat heart (p < 0.02). CONCLUSIONS: Long-term exposure to 2.1 GHz EMF decreases β-AR responsiveness of ventricular myocytes through NO signaling.

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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; isolated ventricular myocytes and heart tissue samples

Sample sizeNot supplied

ExposureRF · 2100 MHz · 2 h/day for 10 weeks

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Outcomes measured

Ventricular myocyte contractility (fractional/sarcomere shortening)
Intracellular Ca2+ transients amplitude (Fura2-AM)
L-type Ca2+ current density (ICaL), basal and isoproterenol-induced (β-adrenergic responsiveness)
Cardiac nitric oxide (NO) levels

Limitations

Sample size not reported in abstract
Specific exposure metrics beyond frequency and schedule (e.g., SAR, field strength) not reported in abstract
Outcomes are ex vivo measurements in isolated myocytes/tissue rather than in vivo cardiac function

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 2100,
    "sar_wkg": null,
    "duration": "2 h/day for 10 weeks"
  },
  "population": "Rats; isolated ventricular myocytes and heart tissue samples",
  "sample_size": null,
  "outcomes": [
    "Ventricular myocyte contractility (fractional/sarcomere shortening)",
    "Intracellular Ca2+ transients amplitude (Fura2-AM)",
    "L-type Ca2+ current density (ICaL), basal and isoproterenol-induced (β-adrenergic responsiveness)",
    "Cardiac nitric oxide (NO) levels"
  ],
  "main_findings": "In rats exposed to 2.1 GHz EMF for 2 h/day for 10 weeks, fractional shortening and matched Ca2+ transient amplitude were not changed versus sham. Basal ICaL density was similar between groups, but the isoproterenol-induced ICaL response was reduced in exposed rats, alongside increased cardiac nitric oxide levels.",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not reported in abstract",
    "Specific exposure metrics beyond frequency and schedule (e.g., SAR, field strength) not reported in abstract",
    "Outcomes are ex vivo measurements in isolated myocytes/tissue rather than in vivo cardiac function"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "2.1 GHz",
    "RF-EMF",
    "rat",
    "ventricular myocytes",
    "contractility",
    "Ca2+ transients",
    "L-type calcium current",
    "beta-adrenergic responsiveness",
    "isoproterenol",
    "nitric oxide"
  ],
  "suggested_hubs": [
    {
      "slug": "mobile-phones",
      "weight": 0.7,
      "reason": "Exposure described as 2.1 GHz EMF in context of mobile phone use."
    }
  ]
}

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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: 10.3109/09553002.2015.1068462
PubMed: 26136087

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