Study type: Medical/biological study (experimental study)

Exposure to extremely low-frequency electromagnetic fields inhibits T-type calcium channels via AA/LTE signaling pathway med./bio.

Published in: Cell Calcium 2014; 55 (1): 48-58

Aim of study (acc. to author)

To investigate the effects of extremely low frequency magnetic fields on human T-type calcium channels transfected in embryonic kidney cells and on native T-type calcium channels in cultured mouse cortical neurons.

Background/further details

T-type calcium channels are low-voltage activated calcium channels. They play key roles in various physiological and pathological functions.
The T-type calcium channels Cav3.1, Cav3.2 and Cav3.3 were transfected in human embryonic kidney cells.
The primary cultured cortical neurons were used to test whether magnetic field exposure inhibits native T-type channel currents via a leukotriene E4 pathway.
Leukotriene E4 is produced by the oxidation of arachidonic acid and involved in inflammation processes.
Experiments were partially performed with the inhibitors CAY10502 (inhibits the release of arachidonic acid), BAYµ9773 (leukotriene receptor antagonist) or bestatin (blocks the conversion from leukotrien D4 to leukotrien E4).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuously for up to 3 hours (0.5 h, 1 h, 2 h, 3 h)

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
  • unspecified
Exposure duration continuously for up to 3 hours (0.5 h, 1 h, 2 h, 3 h)
Exposure setup
Exposure source
Setup magnetic field was produced by a pair of Helmholtz coils, powered by an AC generator system; exposure did not change the temperature of the CO2 incubator (37 °C)
Sham exposure A sham exposure was conducted.
Additional info sham exosed control group was placed in the same incubator but without magnetic field
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 200 µT unspecified measured - -

Reference articles

  • He YL et al. (2013): Exposure to Extremely Low-Frequency Electromagnetic Fields Modulates Na(+) Currents in Rat Cerebellar Granule Cells through Increase of AA/PGE(2) and EP Receptor-Mediated cAMP/PKA Pathway

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

In exposed cell cultures of embryonic kidney cells, the cell currents were significantly decreased after 0.5 and 1 hour exposure compared to the control group. That means that the T-type channels (Cav3.1, Cav3.2 and Cav3.3) were inhibited. The inhibitor CAY10502 and bestatin abrogated the exposure-related inhibitory effect. To further verify the results, leukotriene E4 was added to the culture medium, which mimicked the exposure-related inhibition of calcium channels. However, neither the expression of the T-type channel Cav3.2 nor the steady-state activation and inactivation kinetics were changed by exposure. Arachidonic acid and leukotriene E4 were significantly increased after 0.5 and 1 hour exposure in comparison to the control group.
In primary cultured mouse cortical neurons, the exposure significantly inhibited the T-type channel currents when compared to the control group. Experiments with the inhibitor bestatin and addition of leukotriene E4 indicated that the inhibition is mediated via a leukotriene E4 pathway.
The authors conclude that extremely low frequency magnetic fields inhibit T-type calcium channels in transfected embryonic kidney cells and primary cultured cortical neurons through an arachidonic acid and leukotriene E4 dependent pathway.

Study character:

Study funded by

Related articles