Study type: Medical/biological study (experimental study)

Low-level microwave irradiations affect central cholinergic activity in the rat med./bio.

By: Lai H, Horita A, Chou CK, Guy AW
Published in: J Neurochem 1987; 48 (1): 40-45
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Aim of study (acc. to author)

To study the effect of acute exposure to low-level microwaves on cholinergic activity in the brain of rats. In addition, the authors also investigated whether a narcotic antagonist (naltrexone hydrochloride, naloxone hydrochloride) could block the effects of microwaves on choline uptake in the CNS.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.45 GHz
Modulation type: pulsed
Exposure duration: continuous for 45 min
  • power density: 1 mW/cm² spatial average
  • SAR: 0.6 W/kg average over mass (whole body)
Exposure 2: 2.45 GHz
Modulation type: CW
Exposure duration: continuous for 45 min
  • power density: 1 mW/cm² spatial average
  • SAR: 0.6 W/kg average over mass (whole body)

Exposure 1

Main characteristics
Frequency 2.45 GHz
Type
Charakteristic
  • guided field
Polarization
  • circular
Exposure duration continuous for 45 min
Modulation
Modulation type pulsed
Pulse width 2 µs
Repetition frequency 500 Hz
Exposure setup
Exposure source
Setup The exposure system consisted of eight individual cylindrical waveguide exposure tubes made of galvanized wire screen and operating in TE11 mode. Each tube contained a plastic chamber to house a rat.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power density 1 mW/cm² spatial average - - -
SAR 0.6 W/kg average over mass measured whole body -
Measurement and calculation details

SAR was determined calorimetrically [Chou et al., 1984].

Exposure 2

Main characteristics
Frequency 2.45 GHz
Type
Charakteristic
  • guided field
Polarization
  • circular
Exposure duration continuous for 45 min
Modulation
Modulation type CW
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power density 1 mW/cm² spatial average - - -
SAR 0.6 W/kg average over mass measured whole body -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Pulsed microwave exposure decreased choline uptake in the hippocampus and frontal cortex but had no significant effect on the hypothalamus, striatum, and inferior colliculus. Pretreatment with naloxone or naltrexone blocked the effect of pulsed microwaves on hippocampal choline uptake but did not significantly alter the effect on the frontal cortex.
Exposure to continuous wave (CW) microwaves did not significantly affect choline uptake in the hippocampus, striatum, and hypothalamus but decreased the uptake in the frontal cortex. The effect on the frontal cortex was not changed by pretreatment with narcotic antagonist.
The results suggest that irradiation with low-level pulsed or continuous wave (CW) microwaves leads to changes in cholinergic functions in the brain.

Study character:

Study funded by

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