Study type: Medical/biological study (experimental study)

Effects of two different waveforms of ELF MFs on bioelectrical activity of antennal lobe neurons of Morimus funereus (Insecta, Coleoptera). med./bio.

Published in: Int J Radiat Biol 2015; 91 (5): 435-442

Aim of study (acc. to author)

The effects of exposure of longhorn beetles to a sine wave or square wave 50 Hz magnetic field on the neuronal activity in the antennal lobe (part of the insect brain which receives the input from the olfactory sensory neurons on the antenna) should be investigated.

Background/further details

The longhorn beetle was used as it had already been known to be sensitive to static magnetic fields (see Todorovic et al. 2007) and moreover, because it is particularly relevant as an endangered species in Europe. 22 beetles were divided into the following two groups: 1) exposure to sine waves (n=12), 2) exposure to square waves (n=10). Each beetle was subsequently exposed for 5, 10 and 15 minutes at 40 minutes intervals. The neuronal activity was recorded for 5 minutes directly before and after an exposure session, respectively. The very first record was defined as the sham exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 5, 10 and 15 minutes with 40 minutes intervals in between within 2 h
Exposure 2: 50 Hz
Exposure duration: continuous for 5, 10 and 15 minutes with 40 minutes intervals in between within 2 h

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 5, 10 and 15 minutes with 40 minutes intervals in between within 2 h
Additional info sine waves
Exposure setup
Exposure source
Distance between exposed object and exposure source 1 cm
Setup animals were attached to a plexiglas horizontal plate with an opening for the head in a Faraday cage with 23°C and humidity of 50-60%; a cylindrical Teflon coil (l=70 mm, R=30 mm) containing enameled copper wire coiled around a soft iron core with 8 mm in diameter was placed at a distance of about 1 cm from the insect's left antenna
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT mean measured - on the surface of the head
magnetic flux density 19 mT - measured - on top of the coil iron core

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
  • rectangular
Exposure duration continuous for 5, 10 and 15 minutes with 40 minutes intervals in between within 2 h
Additional info square waves
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT mean measured - on the surface of the head
magnetic flux density 19 mT - measured - on top of the coil iron core

Reference articles

  • Ilijin L et al. (2011): The response of dorsomedial A1' and dorsolateral L2' neurosecretory neurons of Lymantria dispar L. caterpillars to the acute effects of magnetic fields.
  • Pozzi D et al. (2007): Effect of 50 Hz magnetic field exposure on neuroblastoma morphology.
  • Todorovic D et al. (2007): A method for detecting the effect of magnetic field on activity changes of neuronal populations of Morimus funereus (coleoptera, cerambycidae).
  • Prolic Z et al. (2003): Behavioral differences of the insect Morimus funereus (Coleoptera, Cerambycidae) exposed to an extremely low frequency magnetic field.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

No significant differences were found in the neuronal activity of the antennal lobe between the exposure to a sine wave magnetic field and the sham exposure. For the exposure to the square wave magnetic field, significant but reversible changes were detected after the exposure for 15 minutes compared to the measurement after the exposure for 10 minutes.
The results indicate that exposure of longhorn beetles to a square wave 50 Hz magnetic field could influence the neuronal activity in the antennal lobe.

Study character:

Study funded by

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