Medical/biological study (experimental study)

Effect of short-term 50 Hz electromagnetic field exposure on the behavior of rats med./bio.

By: Balassa T, Szemerszky R, Bardos G

Published in: Acta Physiol Hung 2009; 96 (4): 437-448

Aim of study (acc. to author)

To create an animal model system to study the possible non-specific symptoms (e.g. dizziness, headache, sickness in the stomach, nausea, etc.) generated by electromagnetic field exposure and to verify or to reject the existence of a biological background to the complaints.

Background/further details

80 rats were divided into the following groups: 1) 20 Sprague-Dawley rats for the elevated plus maze test (10 exposed rats and 10 controls), 2) 20 Sprague-Dawley rats for the novel object exploration test (10 exposed rats and 10 controls), 3) 20 Wistar rats for the social interaction test (studied on five consecutive days), 4) 20 Wistar rats for territoriality test (10 exposed and 10 controls).

Endpoint

cognitive/behavioral endpoints: anxiety and locomotor activity

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 20 min	magnetic flux density: 470 µT minimum magnetic flux density: 520 µT maximum

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	continuous for 20 min

Exposure setup

Exposure source	Helmholtz coils
Setup	pair of Helmholtz coils with an inner diameter of 42 cm, consisting of 240 turns of insulated copper wire; coils 20 cm apart; rats placed in plastic boxes in the center of the coil system

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	470 µT	minimum	measured	-	-
magnetic flux density	520 µT	maximum	measured	-	-

Exposed system:

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: situational anxiety and locomotor activity (elevated plus maze test: e.g. time/number of entries in the open/closed arm, time spent in the central part, number of rearings; novel object exploration test: approach and manipulation), social anxiety: social interaction test and territoriality test (with a strange conspecific: aggression behaviour (e.g. attacking, biting, defending, dominant/subordinate position)); video recording

Investigated system:

investigation on living organism

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The data show that the electromagnetic field exposure may influence general behavior. As for the general activity pattern (estimated in the elevated plus maze), rats seemed to become more passive right after the termination of exposure as compared to the controls. Findings of the novel object exploration test suggest that post exposure passivity remains even if the animals are motivated to explore by presenting an unfamiliar object in a familiar setting (home cage).
On the other hand, neither social interactions nor territorial behaviour have changed due to the electromagnetic field exposure.
The authors conclude that short-term exposure (20 min.) to an extremely low frequency electromagnetic field may not change (or at least not in the range of the applied tests) social anxiety whereas situational anxiety may increase for some extent.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Hungarian Scientific Research Fund (OTKA), Hungary

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