Study type: Medical/biological study (experimental study)

Thermoregulatory responses of rats exposed to 9.3-GHz microwaves: a comparison of E and H orientation. med./bio.

Published in: Physiol Chem Phys Med NMR 1992; 24 (1): 1-10

Aim of study (acc. to author)

The aim of this study was to determine the effects of exposure orientation relative to electric and magnetic fields (E (long axis of body parallel to electric field)- and H (long axis of body parallel to magnetic field)-orientation) on the thermal, cardiovascular, and respiratory changes in anesthetized rats exposed to continuous wave 9.3 GHz radiofrequency irradiation.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 9.3 GHz
Modulation type: CW
Exposure duration: intermittent*
Exposure 2: 9.3 GHz
Modulation type: CW
Exposure duration: intermittent*

General information

*The exposure was discontinued when the colonic temperature increased to 39.5°C and it was initiated again when the temperature returned to 38.5°C. This procedure was continued for 3 cycles.

Exposure 1

Main characteristics
Frequency 9.3 GHz
Type
Charakteristic
Polarization
Exposure duration intermittent*
Additional info Animals were exposed in E-orientation (long axis parallel to electric field)
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.5 m
Chamber Eccosorb RF-shielded anechoic chamber
Setup Rats placed on a holder
Additional info The holder consisted of seven 0.5 cm (O.D) Plexiglas rods mounted in a semicircular pattern on 4 cm x 6 cm Plexiglas plates (0.5 cm thick). Colonic rise and recovery time were 15.2 ± 0.8 min and 24.4 ± 1.3 min respectively.
Parameters
Measurand Value Type Method Mass Remarks
power density 790 W/m² unspecified measured - -
SAR 12.5 mW/g mean - whole body -

Exposure 2

Main characteristics
Frequency 9.3 GHz
Type
Charakteristic
Polarization
Exposure duration intermittent*
Additional info Animals were exposed in H-orientation (long axis parallel to magnetic field)
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.5 m
Additional info Colonic rise and recovery time were 15.0 ± 0.9 min and 26.0 ± 2.3 min respectively.
Parameters
Measurand Value Type Method Mass Remarks
SAR 12.5 mW/g mean - whole body -
power density 590 W/m² unspecified measured - H orientation.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The right subcutaneous temperature change during E-orientation irradiation was considerably less than the colonic temperature change. The tympanic temperature and right subcutaneous temperature (H-orientation) alterations approximated the colonic temperature increase. The subcutaneous left temperature and tail temperature changes (both orientations) were considerably greater than the colonic temperature increase. The tympanic temperature and subcutaneous left temperature increases were virtually equal under the two irradiation conditions; however, the subcutaneous right temperature increase was significantly greater during H-orientation exposure, and the tail temperature increase was significantly greater during E-orientation irradiation.
Heart rate and mean arterial pressure increased significantly during exposure; however the cardiovascular responses were not affected by irradiation orientation.

Study character:

Study funded by

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