Study type: Medical/biological study (experimental study)

Effects of weak environmental magnetic fields on the spontaneous bioelectrical activity of snail neurons. med./bio.

Published in: J Membr Biol 2011; 240 (2): 63-71

Aim of study (acc. to author)

To study the effects of 50 Hz magnetic fields in the range of magnetic flux densities relevant to current environmental exposures on action potential, after-hyperpolarization potential and neuronal excitability in neurons of land snails (Helix aspersa).

Background/further details

All experiments were performed on single neuron units (F1; n=42) located in the visceral ganglion of the snail.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 18 min or 20 min (see "additional information")

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 18 min or 20 min (see "additional information")
Exposure setup
Exposure source
Setup pair of Helmholtz coils with a diameter of 20 cm, spaced 10 cm apart, consisting each of 325 turns of 0.5 mm copper wire; field homogeneity better than 0.1 µT in the exposure area inside the coils
Additional info exposure time: 18 min exposure - 2 min examination without exposure - additional 2 min exposure (= 20 min)
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 207.2 µT effective value measured - 2.83 µT, 6.02 µT, 14.91 µT, 45.87 µT, 109.34 µT, 207.2 µT in the exposure area within the coils

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

When the neurons were exposed to magnetic fields at the various magnetic flux densities, marked changes in neuronal excitability, firing rate (decrease, i.e. inhibition of neuronal activity) and after-hyperpolarization potential amplitude (increase) were found. These effects seemed to be related to the intensity, type (single and continuous or repeated and cumulative) and length of exposure (18 or 20 min). The extremely low frequency magnetic field exposures affected the excitability of F1 neuronal cells in a nonmonotonic manner, disrupting their normal characteristic and synchronized firing patterns.

Study character:

Study funded by

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