Study type: Medical/biological study (experimental study)

Sinusoidal ELF magnetic fields affect acetylcholinesterase activity in cerebellum synaptosomal membranes. med./bio.

Published in: Bioelectromagnetics 2010; 31 (4): 270-276

Aim of study (acc. to author)

To study effects of extremely low frequency magnetic fields or of static magnetic fields with amplitudes from 0.5-2.0 mT on acetylcholinesterase enzyme activity of murine synaptosomal membranes.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 5 min
Exposure 2: 50 Hz
Exposure duration: continuous for 1 min
Exposure 3: 10–650 Hz
Exposure duration: continuous for 1 min
Exposure 4:
Exposure duration: continuous for 5 min
Exposure 5:
Exposure duration: continuous for 1 min

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 5 min
Exposure setup
Exposure source
Setup coil consisting of 100 turns of 0.5 mm diameter copper wire with 0.1 mm insulation wound around a 6 cm high cylindrical plexiglass sample holder with a diameter of 2 cm; 4 cm high 1 cm x 1 cm polycarbonate cuvette placed in the center of the sample holder; uniform MF in the sample holder
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT maximum calculated - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 1 min
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.25 mT minimum calculated - -
magnetic flux density 2 mT maximum calculated - -

Exposure 3

Main characteristics
Frequency 10–650 Hz
Type
Waveform
Exposure duration continuous for 1 min
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT maximum calculated - -

Exposure 4

Main characteristics
Frequency
Type
Exposure duration continuous for 5 min
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT maximum calculated - -

Exposure 5

Main characteristics
Frequency
Type
Exposure duration continuous for 1 min
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.4 mT minimum calculated - -
magnetic flux density 1.6 mT maximum calculated - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Exposures to sinusoidal 50 Hz magnetic fields with different amplitudes decreased the acetylcholinesterase enzyme activity by about 27% with a threshold of about 0.74 mT. The decrease in the enzymatic activity was independent of the exposure duration and it was completely reversible (it was detectable only during the field exposure).
Identical results were obtained for exposure to static magnetic fields of the same amplitudes. Moreover, the inhibitory effects on enzyme activity are spread over frequency windows (window effect) with different maximal values at 60, 200, 350, and 475 Hz.
When synaptosomal membranes were solubilized with Triton (solubilize membrane proteins in their native state from membranes), no effect of the magnetic field was revealed on the enzyme activity, suggesting the crucial role of the membrane, as well as the lipid linkage of the enzyme, in determining the conditions for inactivation.

Study character:

Study funded by

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