Study type: Medical/biological study (experimental study)

Permeability changes of connexin32 hemi channels reconstituted in liposomes induced by extremely low frequency, low amplitude magnetic fields med./bio.

By: Ramundo-Orlando A, Serafino A, Schiavo R, Liberti M, D'Inzeo G
Published in: Biochim Biophys Acta Biomembr 2005; 1668 (1): 33-40
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Aim of study (acc. to author)

To study the effect of extremely low frequency and low amplitude magnetic fields on gap junctional (hemi channel) permeability by using purified connexin 32 from rat liver reconstituted into lipid bilayers (liposomes). The effect of exposures to magnetic fields at different frequencies and amplitudes, and at different temperatures (16, 18 and 24°C) was studied.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 7 Hz
Exposure duration: 60 min
Exposure 2: 13 Hz
Exposure duration: 60 min
Exposure 3: 18 Hz
Exposure duration: 60 min

Exposure 1

Main characteristics
Frequency 7 Hz
Type
Exposure duration 60 min
Exposure setup
Exposure source
Setup 8 cm x 8 cm x 8 cm isofield region in the center of the coils system
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 50 µT peak value - - AC
magnetic flux density 70 µT peak value - - AC
magnetic flux density 50 µT - - - DC

Exposure 2

Main characteristics
Frequency 13 Hz
Type
Exposure duration 60 min
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 50 µT peak value - - AC
magnetic flux density 70 µT peak value - - AC
magnetic flux density 50 µT - - - DC

Exposure 3

Main characteristics
Frequency 18 Hz
Type
Exposure duration 60 min
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 70 µT peak value - - AC
magnetic flux density 50 µT peak value - - AC
magnetic flux density 50 µT - - - DC

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Only the exposure of proteoliposomes to 18-Hz (70 µT) magnetic field for 60 min at 16+/-0.4°C resulted in a significant enhancement of the gap junction permeability. This enhancement was not observed for magnetic field exposures of liposomes kept at the higher temperatures tested. Temperature appears to influence lipid bilayer arrangement in such a way as being capable to mask possible effects induced by the magnetic field. Although the revealed effect was very low, it seems to confirm the applicability of the author's model previously proposed for the interaction of low frequency electromagnetic fields with lipid membrane (see publication 3933).

Study character:

Study funded by

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