Study type: Medical/biological study (experimental study)

The effects of hyperthermia and hyperthermia plus microwaves on rat brain energy metabolism. med./bio.

Published in: Bioelectromagnetics 1984; 5 (1): 63-70

Aim of study (acc. to author)

To study the effects of hyperthermia, alone and in conjunction with microwave exposure, on brain energy metabolism (reflected in brain ATP and CP (creatine phosphate)-concentration) in rats. The effect of temperature on ATP and CP was determined in the brains that were maintained at 35.6, 37, 39, and 41°C.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 591 MHz
Modulation type: CW
Exposure duration: 0.5, 1.0, 3.0 and 5.0 min

Exposure 1

Main characteristics
Frequency 591 MHz
Type
Exposure duration 0.5, 1.0, 3.0 and 5.0 min
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 0.03 m
Additional info Generator AIL 125A. EF parallel to the body axis.
Parameters
Measurand Value Type Method Mass Remarks
power density 138 W/m² unspecified measured - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

At 37, 39, and 41°C brain ATP concentration was down 6, 10.8, and 29.2% from the 35.6°C control concentration and creatine phosphate concentration was 19.6, 28.7, and 44% from the 35.6°C control concentration. Irradiation of the brain to 591 MHz (13.8 mW/cm²) for 0.5, 1, 3, and 5 min caused further decreases (below those observed for hyperthermia only) of 16, 29.8, 22.5, and 12.3% in brain ATP concentration, and of 15.6, 25.1, 21.4, and 25.9% in brain creatine phosphate concentration. Recording of brain NADH fluorescence before, during, and after microwave irradiation showed an increase in NADH fluorescence during microwave exposure that returned to preexposure levels within 1 min postexposure. Continuous recordings of brain temperatures during exposures showed that brain temperature varied between -0.1 and +0.05°C. So the microwave irradiations did not induce tissue hyperthermia, and it is concluded that direct microwave interaction at the subcellular level is responsible for the observed decrease in ATP- and CP-concentration.

Study character:

Study funded by

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