Study type: Medical/biological study (experimental study)

Effects of exposure to extremely low frequency electromagnetic fields on hippocampal long-term potentiation in hippocampal CA1 region. med./bio.

Published in: Biochem Biophys Res Commun 2019; 517 (3): 513-519

Aim of study (acc. to author)

The effects of exposure to extremely low frequency magnetic fields on synaptic plasticity in rat hippocampus should be investigated.

Background/further details

Hippocampal slices from young rats were either used in a control group or exposed to magnetic fields with different combinations of frequency (15, 50 and 100 Hz), magnetic flux density (0.5, 1, and 2 mT) and exposure duration (10 s, 20 s, 40 s, 60 s and 5 min). First the baseline signal of excitatory postsynaptic potentials was recorded for 20 min, then the exposure started and recording continued for further 60 min.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 15–100 Hz
Exposure duration: 10 s, 20 s, 40 s, 60 s and 5 min
Exposure 2: 15–100 Hz
Exposure duration: 10 s, 20 s, 40 s, 60 s and 5 min
Exposure 3: 15–100 Hz
Exposure duration: 10 s, 20 s, 40 s, 60 s and 5 min

Exposure 1

Main characteristics
Frequency 15–100 Hz
Type
Waveform
Exposure duration 10 s, 20 s, 40 s, 60 s and 5 min
Exposure setup
Exposure source
Setup two four-coils system were placed into metal boxes for exposure and control group; an incubator was placed above these to control the temperature at 33°C; both the dish holder and a mu-metal box were placed on elastically damped feet in order to minimize vibration; the temperature of the flasks monitored during exposure
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.5 mT - measured and calculated - -

Exposure 2

Main characteristics
Frequency 15–100 Hz
Type
Waveform
Exposure duration 10 s, 20 s, 40 s, 60 s and 5 min
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1 mT - measured and calculated - -

Exposure 3

Main characteristics
Frequency 15–100 Hz
Type
Waveform
Exposure duration 10 s, 20 s, 40 s, 60 s and 5 min
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT - measured and calculated - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Exposure to the magnetic field significantly decreased the amplitude of excitatory postsynaptic potentials in all investigated combinations of frequency, magnetic flux density and exposure duration compared to the control group. The reduction of excitatory postsynaptic potentials was proportional to magnetic flux density and exposure duration, the most distinct inhibition was measured in exposure to a 15 Hz magnetic field at 2 mT for 5 min.
The authors conclude that exposure to extremely low frequency magnetic fields could influence synaptic plasticity in rat hippocampus.

Study character:

Study funded by

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