Comparison of biological effects of electromagnetic fields with pulse frequencies of 8 and 50 Hz on gastric smooth muscles.

Electromagnetic biology and medicine · 2016 · Mixed · Low evidence

← Research stream

MixedLow evidencePaper 4763

Study snapshot

PublicationElectromagnetic biology and medicine · 2016

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

The influence of electromagnetic fields (EMFs) with rectangular pulse frequencies of 8 and 50 Hz and flux density of 25 µT on contraction, nitric oxide/nitrite synthesis, and intracellular calcium concentration in the gastric smooth muscles of rats was investigated. An approximately 8-Hz field reduced the fast component of contraction induced by KCl depolarization and slowed down the time to reach the maximum of the slow component of contraction, whereas the 50-Hz field increased the fast and slow components and accelerated the time to reach the maximum of the slow component of contraction. After turning off the EMF, the force and character of contraction returned to the control values. In addition, the 8-Hz field increased nitric oxide/nitrite synthesis in the excited smooth muscle tissue with KCl depolarization, while the 50-Hz field had no significant effect. 8- and 50-Hz fields had no significant effects on nitric oxide/nitrite production in non-stimulated tissue. However, the 50-Hz field significantly increased the basic intracellular calcium concentration in smooth muscle cells (SMC) in a time-dependent manner, whereas the 8-Hz field only slightly increased calcium levels. Thus, we showed that responses of gastric smooth muscles to EMFs are pulse-frequency dependent.

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

PopulationRats (gastric smooth muscle tissue/cells)

Sample sizeNot supplied

ExposureELF

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Rectangular-pulse EMFs at 25 µT produced pulse-frequency–dependent effects in rat gastric smooth muscle. An ~8 Hz field reduced the fast component of KCl-induced contraction and slowed the time to maximum of the slow component, increased nitric oxide/nitrite synthesis in KCl-depolarized tissue, and only slightly increased intracellular calcium. A 50 Hz field increased fast and slow contraction components and accelerated time to maximum of the slow component, had no significant effect on nitric oxide/nitrite synthesis, and significantly increased basal intracellular calcium in a time-dependent manner; effects on contraction returned to control after EMF was turned off.

Outcomes measured

Gastric smooth muscle contraction (fast and slow components; time to maximum)
Nitric oxide/nitrite synthesis/production
Intracellular calcium concentration in smooth muscle cells

Limitations

Sample size not reported in abstract
Exposure duration not specified in abstract
Animal/tissue study; generalizability to humans not addressed in abstract

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Rats (gastric smooth muscle tissue/cells)",
  "sample_size": null,
  "outcomes": [
    "Gastric smooth muscle contraction (fast and slow components; time to maximum)",
    "Nitric oxide/nitrite synthesis/production",
    "Intracellular calcium concentration in smooth muscle cells"
  ],
  "main_findings": "Rectangular-pulse EMFs at 25 µT produced pulse-frequency–dependent effects in rat gastric smooth muscle. An ~8 Hz field reduced the fast component of KCl-induced contraction and slowed the time to maximum of the slow component, increased nitric oxide/nitrite synthesis in KCl-depolarized tissue, and only slightly increased intracellular calcium. A 50 Hz field increased fast and slow contraction components and accelerated time to maximum of the slow component, had no significant effect on nitric oxide/nitrite synthesis, and significantly increased basal intracellular calcium in a time-dependent manner; effects on contraction returned to control after EMF was turned off.",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not reported in abstract",
    "Exposure duration not specified in abstract",
    "Animal/tissue study; generalizability to humans not addressed in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF EMF",
    "rectangular pulse",
    "8 Hz",
    "50 Hz",
    "25 µT",
    "gastric smooth muscle",
    "rat",
    "contraction",
    "nitric oxide",
    "nitrite",
    "intracellular calcium",
    "KCl depolarization"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.2,
      "reason": "Study involves ELF frequencies (8 and 50 Hz), which can be relevant to occupational ELF contexts, though no specific source is stated."
    }
  ]
}

AI can be wrong. Always verify against the paper.

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: 10.3109/15368378.2015.1028072
PubMed: 26192248

Read the original paper →

Related papers

← Back to the Research Library