Study type: Medical/biological study (experimental study)

Temporal patterns of extremely low frequency magnetic field-induced motor behavior changes in Mongolian gerbils of different age. med./bio.

Published in: Int J Radiat Biol 2012; 88 (4): 359-366

Aim of study (acc. to author)

To study the effects of a seven-day exposure to an extremely low frequency magnetic field on different behaviour parameters in gerbils of different age. The behaviour parameters were investigated on the 1st, 2nd, 4th, and 7th day of exposure (immediate effect) and three days after exposure has been ceased (delayed effect).

Background/further details

The following main groups were investigated: three-month-old male gerbils (n = 35) and ten-month-old male gerbils (n = 35).
The animals were divided into two control groups (cage control and sham exposed) and three exposure groups (0.1, 0.25 and 0.5 mT).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 7 days

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 7 days
Exposure setup
Exposure source
Chamber gerbils were exposed in standard polycarbonate cages (26 cm x 43 cm x 15 cm); simultaneously, two cages with 3-4 gerbils were placed in the vicinity of ELF-MF source for 7 days, one on the left side of the electromagnet and another on the right side
Setup electromagnet with a regular laminated transformer core and pole diameter of 9.5 cm; the center of each cage was at 20, 28 and 40 cm from the electromagnetic poles
Sham exposure A sham exposure was conducted.
Additional info the electromagnet was supplied with a sinusoidal current (50 Hz, 40 V, 4.5 A)
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 8.9 mT maximum measured - on the electromagnetic poles
magnetic flux density 0.5 mT mean - - at a distance of 20 cm
magnetic flux density 0.25 mT mean - - at a distance of 28 cm
magnetic flux density 0.1 mT mean - - at a distance of 40 cm

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Exposure to an extremely low frequency magnetic field for seven days (0.1, 0.25 and 0.5 mT) stimulated motor behaviour (locomotor activity and stereotypy) in 3-month-old gerbils, whereby the most significant changes were observed after the first day of exposure. Simultaneously, a significant reduction of immobility during the entire period of the seven-day exposure was reported. Additionally, exposure to the different extremely low frequency magnetic fields had a delayed effect (except 0.25 mT) on stereotypy (decrease) and immobility (increase).
The effect of the extremely low frequency magnetic fields on the behaviour of ten-month-old gerbils largely depended on the value of the electromagnetic induction. On the first exposure day an extremely low frequency magnetic field of 0.1mT decreased, 0.25 mT had no effect and 0.5 mT increased motor behaviour (locomotor activity and stereotypy). But a significant increase of motor behaviour after the second day of exposure with 0.25 mT was reported. Furthermore, a significant reduction of immobility during the entire period of the seven-day exposure to 0.5 mT was noticed.
Three days after exposure has been ceased (delayed effect), significant stimulation of motor behaviour and reduction of immobility time was observed in all exposed groups compared to the control group.
In conclusion, the results revealed the specific temporal patterns of immediate and delayed motor behaviour changes in three- and ten-month-old gerbils induced by extremely low frequency magnetic fields, which could be due to age-dependent differences in the brain structures (responsible for a control of motor behaviour).

Study character:

Study funded by

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