Extremely Low Frequency Electromagnetic Fields Facilitate Vesicle Endocytosis by Increasing Presynaptic Calcium Channel Expression at a Central Synapse.

Scientific reports · 2016 · Benefit · Low evidence

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BenefitLow evidencePaper 4879

Study snapshot

PublicationScientific reports · 2016

Study typeanimal

Reported directionBenefit

Evidence ratingLow

Abstract

Accumulating evidence suggests significant biological effects caused by extremely low frequency electromagnetic fields (ELF-EMF). Although exo-endocytosis plays crucial physical and biological roles in neuronal communication, studies on how ELF-EMF regulates this process are scarce. By directly measuring calcium currents and membrane capacitance at a large mammalian central nervous synapse, the calyx of Held, we report for the first time that ELF-EMF critically affects synaptic transmission and plasticity. Exposure to ELF-EMF for 8 to 10 days dramatically increases the calcium influx upon stimulation and facilitates all forms of vesicle endocytosis, including slow and rapid endocytosis, endocytosis overshoot and bulk endocytosis, but does not affect the RRP size and exocytosis. Exposure to ELF-EMF also potentiates PTP, a form of short-term plasticity, increasing its peak amplitude without impacting its time course. We further investigated the underlying mechanisms and found that calcium channel expression, including the P/Q, N, and R subtypes, at the presynaptic nerve terminal was enhanced, accounting for the increased calcium influx upon stimulation. Thus, we conclude that exposure to ELF-EMF facilitates vesicle endocytosis and synaptic plasticity in a calcium-dependent manner by increasing calcium channel expression at the nerve terminal.

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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 directionbenefit

PopulationLarge mammalian central nervous synapse (calyx of Held)

Sample sizeNot supplied

ExposureELF · 8 to 10 days

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Exposure to ELF-EMF for 8–10 days increased stimulation-evoked calcium influx and facilitated multiple forms of vesicle endocytosis, without affecting RRP size or exocytosis. ELF-EMF exposure increased the peak amplitude of post-tetanic potentiation without changing its time course, and was associated with enhanced presynaptic calcium channel expression (P/Q, N, R), proposed to account for the increased calcium influx.

Outcomes measured

Calcium currents/influx upon stimulation
Membrane capacitance
Vesicle endocytosis (slow, rapid, overshoot, bulk)
Readily releasable pool (RRP) size
Exocytosis
Synaptic transmission and plasticity
Post-tetanic potentiation (PTP) peak amplitude and time course
Presynaptic calcium channel expression (P/Q, N, R subtypes)

Limitations

Frequency and field strength of ELF-EMF exposure not reported in the abstract
Sample size and detailed experimental design not provided in the abstract
Findings are from an animal/synapse preparation; generalizability to humans not addressed in the abstract

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "8 to 10 days"
  },
  "population": "Large mammalian central nervous synapse (calyx of Held)",
  "sample_size": null,
  "outcomes": [
    "Calcium currents/influx upon stimulation",
    "Membrane capacitance",
    "Vesicle endocytosis (slow, rapid, overshoot, bulk)",
    "Readily releasable pool (RRP) size",
    "Exocytosis",
    "Synaptic transmission and plasticity",
    "Post-tetanic potentiation (PTP) peak amplitude and time course",
    "Presynaptic calcium channel expression (P/Q, N, R subtypes)"
  ],
  "main_findings": "Exposure to ELF-EMF for 8–10 days increased stimulation-evoked calcium influx and facilitated multiple forms of vesicle endocytosis, without affecting RRP size or exocytosis. ELF-EMF exposure increased the peak amplitude of post-tetanic potentiation without changing its time course, and was associated with enhanced presynaptic calcium channel expression (P/Q, N, R), proposed to account for the increased calcium influx.",
  "effect_direction": "benefit",
  "limitations": [
    "Frequency and field strength of ELF-EMF exposure not reported in the abstract",
    "Sample size and detailed experimental design not provided in the abstract",
    "Findings are from an animal/synapse preparation; generalizability to humans not addressed in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF-EMF",
    "calyx of Held",
    "synaptic transmission",
    "synaptic plasticity",
    "vesicle endocytosis",
    "calcium influx",
    "presynaptic calcium channels",
    "P/Q-type",
    "N-type",
    "R-type",
    "post-tetanic potentiation"
  ],
  "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: 10.1038/srep21774
PubMed: 26887777

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