Study type: Medical/biological study (experimental study)

Effects of a time-varying strong magnetic field on transient increase in Ca(2+) release induced by cytosolic Ca(2+) in cultured pheochromocytoma cells med./bio.

By: Ikehara T, Yamaguchi H, Hosokawa K, Houchi H, Park KH, Minakuchi K, Kashimoto H, Kitamura M, Kinouchi Y, Yoshizaki K, Miyamoto H
Published in: Biochimica et Biophysica Acta - General Subjects 2005; 1724 (1-2): 8-16
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Aim of study (acc. to author)

To study the effects of exposure to a time-varying 1.5 T magnetic field on Ca2+ release from intracellular Ca2+ stores mediated by ryanodine and IP3 (inositol trisphosphate) receptors in cells.

Background/further details

After assaying fluorescence in Ca2+-free medium, cells were treated with any one of the drugs such as caffeine, ATP and thapsigargin to induce a transient change in intracellular calcium concentration.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Modulation type: pulsed
Exposure duration: intermittent for 15 min, 30 min, 1 h or 2 hr; 3 s on/off cycle

Exposure 1

Main characteristics
Type
Waveform
Exposure duration intermittent for 15 min, 30 min, 1 h or 2 hr; 3 s on/off cycle
Modulation
Modulation type pulsed
Exposure setup
Exposure source
Chamber Incubator (129 mm in diameter, 20 mm thick) containing 4 culture dishes and maintained at 37°C
Setup incubator placed in the gap between the two poles of the electromagnet
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.51 T maximum unspecified - -
current density 28 mA/m² mean estimated - 11 mA/m² min value; induced eddy current densities in the medium
Additional parameter details

magnetic field was produced in the magnet's gap of about 20 mm

Reference articles

  • Ikehara T et al. (2002): Effects of a time varying strong magnetic field on release of cytosolic free Ca2+ from intracellular stores in cultured bovine adrenal chromaffin cells

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Exposure of PC-12 cells to a time-varying 1.51 T magnetic field inhibited an increase in the intracellular Ca2+ concentration induced by addition of caffeine to Ca2+-free medium. This inhibition occurred after a 15 min exposure and was maintained for at least two hours.
The intracellular Ca2+ concentration increased in cells loaded with cyclic ADP-ribose (a ryanodine receptor stimulator), and two hours exposure significantly suppressed the increase. Addition of ATP induced a transient increase in intracellular Ca2+ release mediated by inositol trisphosphate receptor. This increase was strongly inhibited by the exposure.
The data indicated that the magnetic field exposure strongly inhibited Ca2+ release mediated by both inositol trisphosphate and ryanodine receptors. However, thapsigargin-induced Ca2+ influx across the cell membrane was unaffected.
The ATP concentration was maintained at the normal level during the 2 h exposure, indicating that ATP hydrolysis was unchanged.

Study character:

Study funded by

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