Study type: Medical/biological study (experimental study)

Extremely low frequency electromagnetic field exposure promotes differentiation of pituitary corticotrope-derived AtT20 D16V cells. med./bio.

Published in: Bioelectromagnetics 2006; 27 (8): 641-651

Aim of study (acc. to author)

To study the effect of extremely low frequency electromagnetic fields at a frequency of 50 Hz on the differentiation activities of the pituitary corticotrope-derived AtT20 D16V cell line.

Background/further details

The cells are electrically excitable, possess high voltage-activated calcium channels, and are a good model to study the effects of extremely low frequency electromagnetic field exposure on the calcium (Ca2+)-dependent signal transmission cascade. This cell line responds to nerve growth factor by extending neurite-like processes and differentiating into neurosecretory-like cells.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: initiated at 300 s till 660 sec
Exposure 2: 50 Hz
Exposure duration: continuous for 24 h or 48 h

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration initiated at 300 s till 660 sec
Exposure setup
Exposure source
Distance between exposed object and exposure source 2 mm
Setup The coil was lowered into the incubation chamber which was movable to get the desired MF at the location of the sample. The adherent cells on a glass cover slip were positioned 2 mm below the coil. For sham control, the current was passed into the two coil windings in opposite directions to obtain zero MF at the same time producing the same heat (37°C) as exposure experiments.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT effective value measured - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 24 h or 48 h
Exposure setup
Exposure source
Distance between exposed object and exposure source 2 mm
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT effective value measured - -

Reference articles

  • Santoro N et al. (1997): Effect of extremely low frequency (ELF) magnetic field exposure on morphological and biophysical properties of human lymphoid cell line (Raji).

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

A statistically significant increase in intracellular calcium followed by a drop in intracellular pH in exposed cells was found. Exposed AtT20 D16V cells showed morphological changes in plasma membrane compared to non-exposed cells; this modification was accompanied by a rearrangement in actin filament distribution and the emergence of properties typical of peptidergic neuronal cells: the appearance of secretory-like granules in the cytosol and the increase of the neuronal differentiation marker synaptophysin in synaptic vesicles.
These findings demonstrate that exposure to 50 Hz extremely low frequency electromagnetic fields is responsible for the premature differentiation in AtT20 D 16 V cells.

Study character:

Study funded by

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