Study type: Medical/biological study (experimental study)

Failure of rats to escape from a potentially lethal microwave field. med./bio.

Published in: Bioelectromagnetics 1980; 1 (2): 101-115

Aim of study (acc. to author)

Rats were repeatedly presented an opportunity to escape from an intense 918 MHz field (60 mW/g) to a field of lower intensity (40, 30, 20, or 2 mW/g) by performing a simple locomotor response. Other rats could escape 800 µA faradic shock to the feet and tail by performing the same response in the same milieu.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 918 MHz
Exposure duration: intermittent; 2 min on/off, 22 min/day for 6 days

Exposure 1

Main characteristics
Frequency 918 MHz
Type
Exposure duration intermittent; 2 min on/off, 22 min/day for 6 days
Modulation
Modulation type cf. additional info
Additional info

A 3 Hz secondary sinusoidal modulation introduced by a three element mode stirrer in the cavity rotating at 1 rev/sec.

Exposure setup
Exposure source
  • modified General electric Model J-845 multimode cavity
Chamber cavity 44.0 x 58.0 x 39.0 cm
Additional info 22 parallel, equidistant 5 mm stripes of conductive silver paint used for 800 µA faradic shock
Parameters
Measurand Value Type Method Mass Remarks
SAR 60 mW/g mean calculated whole body -
SAR 40 mW/g mean calculated whole body -
SAR 30 mW/g mean calculated whole body -
SAR 20 mW/g mean measured whole body -
SAR 2 mW/g mean calculated whole body -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

None of 20 exposed rats learned to associate entry into a visually well-demarcated area of the cavity with immediate reduction of dose rate, in spite of field-induced increases of body temperature to levels that exceeded 41°C. In contrast, all of ten animals motivated by faradic shock learned to escape. The failure of escape learning by exposed rats probably arose from deficiencies of motivation and, especially, sensory feedback. Whole-body hyperthermia may lack the painful or directional sensory properties that optimally promote the motive to escape. Moreover, a decrease of body temperature after an escape-response-contingent reduction of field strength will be relatively slow because of the large thermal time constants of mammalian tissues, so that the animals seem to fail assigning cause and effect.

Study character:

Study funded by

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