Study type: Medical/biological study (experimental study)

The action of pulse-modulated GSM radiation increases regional changes in brain activity and c-Fos expression in cortical and subcortical areas in a rat model of picrotoxin-induced seizure proneness. med./bio.

Published in: J Neurosci Res 2009; 87 (6): 1484-1499

Aim of study (acc. to author)

To assess whether the effects on brain activity of pulse modulated GSM differ from those of a non-modulated signal of the same wavelength and if so to study c-Fos expression in seizure-related [induced by picrotoxin] anatomical circuits.

Background/further details

Male rats were assigned to six groups: 1) injection with picrotoxin [induced seizure-proneness]/no exposure; 2) injection with picrotoxin/exposure to 900 MHz pulse modulated GSM; 3) injection with picrotoxin/exposure to 900 MHz un-modulated signal; 4) no exposure/no picrotoxin; 5) GSM exposure only; and 6) un-modulated signal only.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: CW
Exposure duration: continuous for 2 hr
  • power: 0.26 W
  • SAR: 0.26 W/kg mean (brain)
  • SAR: 0.26 W/kg mean (whole body)
  • SAR: 0.3 W/kg peak value (1 g) (brain)
  • SAR: 1.4 W/kg peak value (1 g) (body)
Exposure 2: 900 MHz
Exposure duration: continuous for 2 hr
  • power: 0.26 W
  • SAR: 0.05 W/kg mean (brain)
  • SAR: 0.06 W/kg peak value (1 g) (brain)
  • SAR: 0.05 W/kg mean (whole body)
  • SAR: 0.28 W/kg peak value (1 g) (body)

General information

rats were assigned to one of the following groups: i) injection of picrotoxin (PT) ii) injection of PT+ pulse-modulated EMF iii) injection of PT + unmodulated EMF iv) no injection of PT + no EMF exposure v) no injection of PT + pulse-modulated EMF vi) no injection of PT + unmodulated EMF

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 2 hr
Modulation
Modulation type CW
Exposure setup
Exposure source
Setup rats placed in 150 cm x 46 cm x 70 cm radiation cage incorporating a commercial transmitting antenna
Parameters
Measurand Value Type Method Mass Remarks
power 0.26 W - - - -
SAR 0.26 W/kg mean estimated brain -
SAR 0.26 W/kg mean estimated whole body -
SAR 0.3 W/kg peak value estimated 1 g brain
SAR 1.4 W/kg peak value estimated 1 g body

Exposure 2

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 2 hr
Modulation
Modulation type cf. additional info
Additional info

GSM

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power 0.26 W - - - -
SAR 0.05 W/kg mean estimated brain -
SAR 0.06 W/kg peak value estimated 1 g brain
SAR 0.05 W/kg mean estimated whole body -
SAR 0.28 W/kg peak value estimated 1 g body

Reference articles

  • Fritze K et al. (1997): Effect of global system for mobile communication microwave exposure on the genomic response of the rat brain.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Picrotoxin-treated rats showed no significant EEG abnormalities and all brain areas showed c-Fos expression, with or without posterior exposure (group 1-3). GSM-exposed picrotoxin-pretreated rats (group 2) showed differences in EEG-signs, and in c-Fos expression in the brain, with respect to picrotoxin-treated rats exposed to an equivalent dose of un-modulated exposure (group 3). In group 2, GSM-exposure induced seizures and increased c-Fos-positive neuron counts and the most marked effects were observed in limbic structures, piriform cortex areas and subcortical areas.
Non-picrotoxin-treated animals exposed to un-modulated radiation (group 6) showed the highest levels of neuronal c-Fos expression in cortical areas compared to GSM-exposure (group 5) or no exposure (group 4).
For un-modulated signals (group 3 and 6) occasional discharges occured in EEG recording and seizure development was infrequent in picrotoxin-treated animals (group 3). There was no significant difference in c-Fos expression between non-picrotoxin-treated rats (group 6) and picrotoxin-treated rats (group 3) for un-modulated signals.
900 MHz GSM exposure increased the neuronal excitability in picrotoxin-treated rats, as manifested by behavioral indicators (seizures), EEG indicators, and neuronal c-Fos expression, with respect to rats exposed to unmodulated exposure.

Study character:

Study funded by

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