Study type: Medical/biological study (experimental study)

Chronic exposure to GSM 1800-MHz microwaves reduces excitatory synaptic activity in cultured hippocampal neurons. med./bio.

Published in: Neurosci Lett 2006; 398 (3): 253-257

Aim of study (acc. to author)

To assess the effects of chronic microwave exposure (GSM, 1800 MHz) on the activity of glutamate receptor channels in cultured hippocampal neurons of rats.

Background/further details

Glutamate receptor channels play a key role in excitatory synaptic transmission. Changes in glutamate receptor function may be involved in the mechanisms of the biological effects of GSM microwaves on brain activity.
One group of glutamate receptors are the ionotropic receptors. These are ligand gated ion channels. Two common glutamate receptors are the NMDA receptor (composed of the subunits NR1 and NR2, which again can have different variants, e.g. NR2A, NR2B) and the AMPA (alpha-amino-3-hydroxy-5-methyl-4-soxazole propionic acid) receptor (composed of the subunits GluR1, GluR2, GluR3, and GluR4) whose agonists include NMDA and AMPA.
In addition, the density of PSD95 was detected in exposed and sham exposed neurons. PSD95, a key component of the postsynaptic density (PSD), aggregates neurotransmitter receptors and downstream enzymes and thus ensures the selective activation of different signal transduction cascades within a single cell.
Cultures of hippocampal neurons were prepared from Sprague-Dawley rats.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1,800 MHz
Modulation type: pulsed
Exposure duration: repeated daily exposure, 15 min/day, for 8 days
  • SAR: 2.4 W/kg

Exposure 1

Main characteristics
Frequency 1,800 MHz
Type
Charakteristic
  • guided field
Exposure duration repeated daily exposure, 15 min/day, for 8 days
Modulation
Modulation type pulsed
Duty cycle 12.5 %
Repetition frequency 217 Hz
Pulse type rectangular
Exposure setup
Exposure source
Chamber Two rectangular waveguides, one for RF and one for sham exposure, were placed inside a conventional incubator at 37 °C, 5% CO2, and 95% humidity.
Setup Six 35-mm dishes were positioned in the H field maximum of the standing wave and exposed in E polarisation.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 2.4 W/kg - measured and calculated - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

Chronic exposure to GSM microwaves induced a decrease in the amplitudes of the miniature excitatory postsynaptic currents in AMPA receptors, whereas the amplitudes of NMDA receptors did not change. The frequency of the miniature excitatory postsynaptic currents of the AMPA receptors did not change under exposure.
Chronic exposure did not alter the density of the different receptor subunits.
Chronic microwave exposure induced a decrease in the density of PSD95.
The results indicated that GSM microwaves may reduce excitatory synaptic activity and the number of excitatory synapses in rat hippocampal neurons.

Study character:

Study funded by

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