Study type: Medical/biological study (experimental study)

Effects of an in vivo 60 Hz magnetic field on monoamine levels in mouse brain. med./bio.

Published in: Pathophysiology 2000; 7 (2): 115-119

Aim of study (acc. to author)

The effects of an acute or chronic exposure of mice to different 60 Hz magnetic fields on monoamine levels in the brain should be investigated.

Background/further details

Monoamines are neurotransmitters and neuromodulators and therefore important for the function of the brain.
The following groups were used: 1) exposure of C57BL mice to the magnetic field with 1 mT for 7 days (n=3), 2) exposure of ICR mice for 12 weeks (n=4), 3) exposure of 1-month-old SAMP8 mice for 6 h (n=4), 4) exposure of 3-month-old SAMP8 mice for 6 h (n=4), 5) exposure of 6-month-old SAMP8 mice for 6 h (n=4), 6) exposure of 9-month-old SAMP8 mice for 6 h (n=4) and 7) exposure of 12-month-old SAMP8 mice for 6 h (n=4). For each group, a separate control group with the same number of animals was used. Moreover, restrained ICR mice were exposed to a magnetic field at their heads with 8) 0.1 mT, 9) 0.33 mT or 10) 1 mT (n=6-15 each). A not-restrained and a restrained control group with the same number of animals were used for groups 8-10.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: continuous for 7 days
C57BL mice
Exposure 2: 60 Hz
Exposure duration: continuous for 12 weeks
ICR mice
Exposure 3: 60 Hz
Exposure duration: continuous for 6 h
SAMP8 mice
Exposure 4: 60 Hz
Exposure duration: continuous for 1 h
ICR mice

General information

mice were killed by exposing the head to microwave irradiation at 3 kW for 0.2 s

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Exposure duration continuous for 7 days
Additional info C57BL mice
Exposure setup
Exposure source
Chamber polypropylene cylinder cage (diameter=12 cm, h=12 cm)
Setup three mice per cage were used; Helmholtz coil with a diameter of 12 cm field created MF with a vertical orientation
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT - measured - at the center of the cage

Exposure 2

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration continuous for 12 weeks
Additional info ICR mice
Exposure setup
Exposure source
  • not specified
Chamber polypropylene mouse cage (11 cm x 25 cm, h=12 cm)
Setup four mice were used per cage; mice were exposed in horizontal direction
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT - measured - at the center of the cage

Exposure 3

Main characteristics
Frequency 60 Hz
Type
Exposure duration continuous for 6 h
Additional info SAMP8 mice
Exposure setup
Exposure source
  • same setup as in E2
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT - measured - at the center of the cage

Exposure 4

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration continuous for 1 h
Additional info ICR mice
Exposure setup
Exposure source
  • not specified
Chamber column (body part: 26 mm diameter, head part: 16 mm diameter); the unrestrained control group was kept in a standard mouse cage
Setup animals confined within the column to restrict movement; mice were exposed in horizontal direction
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.1 mT - measured - at the head
magnetic flux density 0.33 mT - measured - at the head
magnetic flux density 1 mT - measured - at the head

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

No significant changes could be observed in groups 1-7 compared to their respective control groups.
The levels of 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindoleacetic acid were significantly increased in several brain regions in groups 8-10 compared to the not-restrained control group without showing a distinct trend. However, the restrained control group showed increased values in comparison to the not-restrained control group as well (remark EMF-Portal: result contradictory: abstract and discussion vs. result table).
The authors conclude that exposure of mice to a 60 Hz magnetic field might increase the stress caused by restraining and thus influence monoamine levels in the brain.

Study character:

Study funded by

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