Effects of exposure to an extremely low frequency electromagnetic field on hippocampal long-term potentiation in rat.

Brain research · 2014 · Mixed · Low evidence

← Research stream

MixedLow evidencePaper 4693

Rats exposed to a 50 Hz, 100 µT magnetic field for 90 days (2 h/day) showed increased LTP induction in the perforant pathway–dentate gyrus synapses compared with sham and control groups, with significant differences in EPSP slope and PS amplitude. No signific…

Study snapshot

PublicationBrain research · 2014

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

Modern lifestyle exposes nearly all humans to electromagnetic fields, particularly to extremely low frequency electromagnetic fields (ELF-EMFs). Prolonged exposure to ELF-EMFs induces persistent changes in neuronal activity. However, the modulation of synaptic efficiency by ELF-EMFs in vivo is still unclear. In the present study, we investigated whether ELF-EMFs can change induction of long-term potentiation (LTP) and paired-pulse ratio (PPR) in the rat hippocampal area. Twenty-nine adult male Wistar rats were divided into 3 groups (ELF-EMF exposed, sham and control groups). The ELF-EMF group was exposed to a magnetic field for 90 consecutive days (2h/day). ELF-EMFs were produced by a circular coil (50Hz, 100 micro Tesla). The sham-exposed controls were placed in an identical chamber with no electromagnetic field. After this period, rats were deeply anesthetized with urethane (2.0mg/kg) and then a bipolar stimulating and recording electrode was implanted into the perforant pathway (PP) and dentate gyrus (DG), respectively. LTP in hippocampal area was induced by high-frequency stimulation (HFS). Prolonged exposure to ELF-EMFs increased LTP induction. There was a significant difference in the slope of EPSP and amplitude of PS between the ELF-EMF group and other groups. In conclusion, our data suggest that exposure to ELF-EMFs produces a marked change in the synaptic plasticity generated in synapses of the PP-DG. No significant difference in PPR of ELF-EMF group before and after HFS suggests a postsynaptic expression site of LTP.

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

PopulationAdult male Wistar rats

Sample size29

ExposureELF · 0.05 MHz · 90 consecutive days (2 h/day)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Outcomes measured

Hippocampal long-term potentiation (LTP) induction
Paired-pulse ratio (PPR)
EPSP slope
Population spike (PS) amplitude

Limitations

In vivo rat study; findings may not generalize to humans
Exposure described as magnetic field only; no SAR reported
Only adult male rats studied
Sample size per group not provided

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": 0.05,
    "sar_wkg": null,
    "duration": "90 consecutive days (2 h/day)"
  },
  "population": "Adult male Wistar rats",
  "sample_size": 29,
  "outcomes": [
    "Hippocampal long-term potentiation (LTP) induction",
    "Paired-pulse ratio (PPR)",
    "EPSP slope",
    "Population spike (PS) amplitude"
  ],
  "main_findings": "Rats exposed to a 50 Hz, 100 µT magnetic field for 90 days (2 h/day) showed increased LTP induction in the perforant pathway–dentate gyrus synapses compared with sham and control groups, with significant differences in EPSP slope and PS amplitude. No significant difference in PPR before vs after HFS in the ELF-EMF group was reported.",
  "effect_direction": "mixed",
  "limitations": [
    "In vivo rat study; findings may not generalize to humans",
    "Exposure described as magnetic field only; no SAR reported",
    "Only adult male rats studied",
    "Sample size per group not provided"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF-EMF",
    "extremely low frequency",
    "50 Hz",
    "100 microtesla",
    "magnetic field",
    "hippocampus",
    "long-term potentiation",
    "synaptic plasticity",
    "paired-pulse ratio",
    "Wistar rat",
    "perforant pathway",
    "dentate gyrus"
  ],
  "suggested_hubs": []
}

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: 10.1016/j.brainres.2014.03.041
PubMed: 24727530

Read the original paper →

Related papers

← Back to the Research Library