Exposure to extremely low frequency electromagnetic fields alters the calcium dynamics of cultured entorhinal cortex neurons.

Environmental research · 2014 · Mixed · Low evidence

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MixedLow evidencePaper 4648

Study snapshot

PublicationEnvironmental research · 2014

Study typein_vitro

Reported directionMixed

Evidence ratingLow

Abstract

Previous studies have revealed that extremely low frequency electromagnetic field (ELF-EMF) exposure affects neuronal dendritic spine density and NMDAR and AMPAR subunit expressions in the entorhinal cortex (EC). Although calcium signaling has a critical role in control of EC neuronal functions, however, it is still unclear whether the ELF-EMF exposure affects the EC neuronal calcium homeostasis. In the present study, using whole-cell recording and calcium imaging, we record the whole-cell inward currents that contain the voltage-gated calcium currents and show that ELF-EMF (50Hz, 1mT or 3mT, lasting 24h) exposure does not influence these currents. Next, we specifically isolate the high-voltage activated (HVA) and low-voltage activated (LVA) calcium channels-induced currents. Similarly, the activation and inactivation characteristics of these membrane calcium channels are also not influenced by ELF-EMF. Importantly, ELF-EMF exposure reduces the maximum amplitude of the high-K(+)-evoked calcium elevation in EC neurons, which is abolished by thapsigargin, a Ca(2+) ATPase inhibitor, to empty the intracellular calcium stores of EC neurons. Together, these findings indicate that ELF-EMF exposure specifically influences the intracellular calcium dynamics of cultural EC neurons via a calcium channel-independent mechanism.

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 typein_vitro

Effect directionmixed

PopulationCultured entorhinal cortex (EC) neurons

Sample sizeNot supplied

ExposureELF · 5e-05 MHz · 24 h

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

ELF-EMF exposure (50 Hz, 1 mT or 3 mT for 24 h) did not influence whole-cell inward currents containing voltage-gated calcium currents, nor the activation/inactivation characteristics of isolated HVA and LVA calcium channel currents. ELF-EMF exposure reduced the maximum amplitude of high-K(+)-evoked calcium elevation in EC neurons, and this reduction was abolished by thapsigargin, suggesting involvement of intracellular calcium stores via a calcium channel-independent mechanism.

Outcomes measured

Whole-cell inward currents containing voltage-gated calcium currents
High-voltage activated (HVA) calcium channel currents (activation/inactivation characteristics)
Low-voltage activated (LVA) calcium channel currents (activation/inactivation characteristics)
High-K(+)-evoked intracellular calcium elevation (maximum amplitude)
Effect of thapsigargin on ELF-EMF-related changes (intracellular calcium stores involvement)

Limitations

In vitro cultured neuron model; generalizability to in vivo or human exposure is not addressed in the abstract
Sample size and replication details are not provided in the abstract
Exposure setup details beyond frequency, field strength, and duration are not provided in the abstract

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 5e-05,
    "sar_wkg": null,
    "duration": "24 h"
  },
  "population": "Cultured entorhinal cortex (EC) neurons",
  "sample_size": null,
  "outcomes": [
    "Whole-cell inward currents containing voltage-gated calcium currents",
    "High-voltage activated (HVA) calcium channel currents (activation/inactivation characteristics)",
    "Low-voltage activated (LVA) calcium channel currents (activation/inactivation characteristics)",
    "High-K(+)-evoked intracellular calcium elevation (maximum amplitude)",
    "Effect of thapsigargin on ELF-EMF-related changes (intracellular calcium stores involvement)"
  ],
  "main_findings": "ELF-EMF exposure (50 Hz, 1 mT or 3 mT for 24 h) did not influence whole-cell inward currents containing voltage-gated calcium currents, nor the activation/inactivation characteristics of isolated HVA and LVA calcium channel currents. ELF-EMF exposure reduced the maximum amplitude of high-K(+)-evoked calcium elevation in EC neurons, and this reduction was abolished by thapsigargin, suggesting involvement of intracellular calcium stores via a calcium channel-independent mechanism.",
  "effect_direction": "mixed",
  "limitations": [
    "In vitro cultured neuron model; generalizability to in vivo or human exposure is not addressed in the abstract",
    "Sample size and replication details are not provided in the abstract",
    "Exposure setup details beyond frequency, field strength, and duration are not provided in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low frequency",
    "ELF-EMF",
    "50 Hz",
    "1 mT",
    "3 mT",
    "entorhinal cortex",
    "cultured neurons",
    "calcium imaging",
    "whole-cell recording",
    "voltage-gated calcium channels",
    "intracellular calcium stores",
    "thapsigargin"
  ],
  "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: 10.1016/j.envres.2014.09.023
PubMed: 25462671

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