Study type: Medical/biological study (experimental study)

Long-term exposure to extremely low-frequency magnetic fields impairs spatial recognition memory in mice. med./bio.

Published in: Clin Exp Pharmacol Physiol 2008; 35 (7): 797-800

Aim of study (acc. to author)

To study short- (7 days) and long-term (25 days) effects of extremely low frequency magnetic fields on spatial recognition memory in mice (n=23).

Background/further details

A Y-maze was used that is based on the innate tendency of rodents to explore novel environments: During the first trial, the mouse was allowed to explore only two arms of the maze (third arm blocked by a door). During the second trial, the door is opened and all three arms are accessible. Discrimination of novelty versus familiarity can be studied by comparing an animal's exploration of all three arms.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 25 Hz
Exposure duration: 1 h/day first for 7 days, then for another 18 days
Exposure 2: 50 Hz
Exposure duration: 1 h/day first for 7 days, then for another 18 days

Exposure 1

Main characteristics
Frequency 25 Hz
Type
Exposure duration 1 h/day first for 7 days, then for another 18 days
Exposure setup
Exposure source
Setup coil consisting of four layers of 250 turns each wrapped horizontally around a 70 cm x 40 cm x 43 cm plastic frame; mice placed in a plastic box on a wooden table in the center of the coil
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.6 mT - measured - during day 1 to 7
magnetic flux density 0.9 mT - measured - during day 8 to 25

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Exposure duration 1 h/day first for 7 days, then for another 18 days
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.1 mT - measured - during day 1 - 7
magnetic flux density 2 mT - measured - during day 8 - 25

Reference articles

  • Lei Y et al. (2005): Effects of extremely low-frequency electromagnetic fields on morphine-induced conditioned place preferences in rats.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The data indicate that neither short- nor long-term exposure to magnetic fields affects the locomotor activity of mice.
However, long-term exposure to 50 Hz magnetic fields reduces recognition of the novel arm.
The results suggest that extremely low frequency magnetic fields impair spatial recognition memory depending on the field strength and/or duration of exposure.

Study character:

Study funded by

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