Study type: Medical/biological study (experimental study)

Variations of glutamate concentration within synaptic cleft in the presence of electromagnetic fields: an artificial neural networks study. med./bio.

Published in: Neurochem Res 2015; 40 (4): 629-642

Aim of study (acc. to author)

The effects of exposure of rat synaptosomes to different extremely low frequency magnetic fields on the extracellular glutamate concentration should be investigated and a model for prediction of these effects should be developed.

Background/further details

Glutamate is an excitatory neurotransmitter that is released by the majority of central nervous system synapses and is involved in developmental processes, cognitive functions, learning and memory.
Synaptosomes were derived from Wistar rat brains and divided into a total of 33 (remark EMF-Portal: or 34? specifications in the article unclear) exposure groups with random values for the magnetic flux density between 0.1 and 2 mT, the frequency between 50 Hz and 230 Hz and the exposure duration between 15 and 50 minutes. Moreover, an unknown number of samples without exposure was used as a control group. The number of groups and random determination of the exposure parameters were chosen due to the simulation model used.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50–230 Hz
Exposure duration: continuous for 15 to 50 minutes

Exposure 1

Main characteristics
Frequency 50–230 Hz
Type
Waveform
Exposure duration continuous for 15 to 50 minutes
Exposure setup
Exposure source
Setup Helmholtz coils consisted of two parallel coils with 35 cm distance and 35 cm internal diameter, which were made of 1,000 turns of coated copper wire with 1.3 mm diameter; samples were placed in an area of the parallel coils where the magnetic field was uniform and magnetic field lines ran vertically to the coils; samples were kept at 4°C during exposure
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.1 mT minimum measured - further values: 0.3, 0.5, 0.7, 0.9, 1.1, 1.3, 1.5, 1.7 and 1.9 mT
magnetic flux density 2 mT maximum measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The interdependencies of frequency, magnetic flux density and exposure time on the one side and glutamate concentration on the other side were found to be complex. A general tendency towards higher extracellular glutamate concentrations with increasing frequency could be found. For the magnetic flux density, a tendency towards decreasing values up to 1.3 mT and increasing values from 1.3 mT on was found. For the exposure time, a tendency towards increasing values from 40 minutes on was detected.
The results received from the artificial neural networks simulation were within the 95% confidence interval of the experimental data. Hence, the model was confirmed as suitable for the prediction of the extracellular glutamate concentration in synaptosome samples.
The authors conclude that exposure of synaptosomes to different extremely low frequency magnetic fields might affect the extracellular glutamate concentration and that this can be simulated successfully.

Study character:

Study funded by

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