Study type: Medical/biological study (experimental study)

Alterations of cognitive function and 5-HT system in rats after long term microwave exposure. med./bio.

Published in: Physiol Behav 2015; 140: 236-246

Aim of study (acc. to author)

The effects of a chronic exposure of rats to a 2.856 GHz electromagnetic field on memory, serotonin system and the content of some neurotransmitters in the brain should be investigated.

Background/further details

75 rats were divided into the following 5 groups (n=15 each): Exposure to a electromagnetic field with a power of 1) 5 mW/cm2, 2) 10 mW/cm2, 3) 20 mW/cm2 and 4) 30 mW/cm2 or 5) sham exposure. The animals were examined at different time points up to 2 month after exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.856 GHz
Exposure duration: continuous for 6 min. 3 times/week for 6 weeks.
Exposure 2: 2.856 GHz
Exposure duration: continuous for 6 min. 3 times/week for 6 weeks.
Exposure 3: 2.856 GHz
Exposure duration: continuous for 6 min. 3 times/week for 6 weeks.
Exposure 4: 2.856 GHz
Exposure duration: continuous for 6 min. 3 times/week for 6 weeks.

Exposure 1

Main characteristics
Frequency 2.856 GHz
Type
Waveform
Exposure duration continuous for 6 min. 3 times/week for 6 weeks.
Exposure setup
Exposure source
Chamber electromagnetic shield chamber
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power density 5 mW/cm² mean measured - -

Exposure 2

Main characteristics
Frequency 2.856 GHz
Type
Waveform
Exposure duration continuous for 6 min. 3 times/week for 6 weeks.
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power density 10 mW/cm² mean measured - -

Exposure 3

Main characteristics
Frequency 2.856 GHz
Type
Waveform
Exposure duration continuous for 6 min. 3 times/week for 6 weeks.
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power density 20 mW/cm² mean measured - -

Exposure 4

Main characteristics
Frequency 2.856 GHz
Type
Waveform
Exposure duration continuous for 6 min. 3 times/week for 6 weeks.
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power density 30 mW/cm² mean measured - -

Reference articles

  • Wang H et al. (2013): Impairment of long-term potentiation induction is essential for the disruption of spatial memory after microwave exposure.

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 spatial memory was significantly impaired in all exposure groups compared to the sham exposure. In the EEG, significant differences were found between all exposure groups and sham exposure (changes in amplitude, frequency and delta wave power).
Morphological analysis showed karyopyknosis and nucleus deformations in the hippocampus and neuronal degradation in the cortex in all exposure groups but not in the sham exposure. The most severe effects were detected in group 4 (30 mW/cm2).
The content of several neurotransmitters was punctually significantly reduced or increased in different groups and at different time points after exposure compared to the sham exposure without any distinct trend. The monoamine oxidase enzyme activity was significantly reduced 28 days and 2 months after exposure in group 4 compared to sham exposure. The expression rates of 5-HT1AR and 5-HT2CR were significantly increased in group 4 compared to sham exposure at different time points.
The authors conclude that a chronic exposure of rats to a 2.856 GHz electromagnetic field could impair the memory and alter the serotonin system and the content of some neurotransmitters in the brain.

Study character:

Study funded by

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