Study type: Medical/biological study (experimental study)

Effect of Low-Intensity Microwave Radiation on Monoamine Neurotransmitters and Their Key Regulating Enzymes in Rat Brain. med./bio.

Published in: Cell Biochem Biophys 2015; 73 (1): 93-100

Aim of study (acc. to author)

To investigate the effects of exposure to low-intensity microwaves on monoamine neurotransmitter levels and their key regulating enzymes in the brain of rats.

Background/further details

Three groups of rats were examined (n=6 per group): 1.) sham exposure, 2.) 900 MHz microwave exposure and 3.) 1800 MHz microwave exposure.
The enzyme tyrosine hydroxylase catalyzes the reaction to form a precursor for dopamine, which, in turn, is a precursor for the neurotransmitters norepinephrine and epinephrine. Tryptophan hydroxylase is an enzyme involved in the synthesis of the neurotransmitter serotonin.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Exposure duration: 2 hours per day, 5 days per week
Exposure 2: 1,800 MHz
Exposure duration: 2 hours per day, 5 days per week

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration 2 hours per day, 5 days per week
Exposure setup
Exposure source
Distance between exposed object and exposure source 100 cm
Chamber rats were restrained in closed boxes (L: 30 cm x B: 15 cm x H: 20 cm), provided with holes of 1 cm diameter for ventilation and were kept at a distance of 100 cm from the source
Setup GTEM cell was a pyramidal tapered, dual-terminated section (L: 220 cm x B: 120 cm x H: 80 cm); microwave source consisted of a signal generator operating at a frequency range of 9 kHz to 3.2 GHz, an amplifier, a DC regulator and a power meter; microwave chamber was lined with absorbers to minimize reflections
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 0.5953 mW/kg - calculated - -
power 1 mW - - - -

Exposure 2

Main characteristics
Frequency 1,800 MHz
Type
Exposure duration 2 hours per day, 5 days per week
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 0.5835 mW/kg - calculated - -
power 1 mW - - - -

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 levels of the neurotransmitters dopamine, norepinephrine, epinephrine were significantly decreased in exposed rats (900 MHz and 1800 MHz) compared to sham exposed rats. The level of serotonin was also decreased in the exposed groups when compared to the sham exposure, but only significantly in the group exposed to the 1800 MHz microwaves. Additionally, in both exposure groups the gene expression of the enzymes tyrosine hydroxylase and tryptophan hydroxylase was significantly decreased in comparison to the sham exposed animals.
The authors conclude that exposure to low-intensity microwaves influences monoamine neurotransmitter levels and their key regulating enzymes in the brain of rats.

Study character:

Study funded by

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