Study type: Medical/biological study (experimental study)

900 MHz modulated electromagnetic fields accelerate the clathrin-mediated endocytosis pathway. med./bio.

Published in: Bioelectromagnetics 2009; 30 (3): 222-230

Aim of study (acc. to author)

To study the effects of mobile phones electromagnetic fields or its pure, low frequency pulsed electric field component on endocytosis and further to elucidate the molecular mechanisms of GSM-induced increase of endocytosis rate found in a previous study (publication 11586).

Background/further details

Under controlled electromagnetic field or pulsed electric field exposure cells were incubated with drugs (Filipin, ethanol, chlorpromazine) inhibiting the endocytosis mediated by clathrin-coated vesicles or by caveolin-coated vesicles.
In specialized literature, several molecular mechanisms for endocytosis are described: clathrin-dependent endocytosis, caveolin-mediated endocytosis, macro-pinocytosis, and clathrin- and caveolin-independent endocytosis

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 20 min
Exposure 2: 217 Hz
Modulation type: pulsed
Exposure duration: continuous for 30 min

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 20 min
Modulation
Modulation type pulsed
Pulse width 576 µs
Duty cycle 12.5 %
Repetition frequency 217 Hz
Exposure setup
Exposure source
Setup wire patch cell placed inside an enclosure with magnetically loaded, narrowbanded, resonant urethane absorbers, located in a CO2 incubator
Parameters
Measurand Value Type Method Mass Remarks
SAR 3.2 W/kg - calculated - -
SAR 0.9 W/kg - measured and calculated - at the center of the Petri dish bottom

Exposure 2

Main characteristics
Frequency 217 Hz
Type
Waveform
  • rectangular
Exposure duration continuous for 30 min
Modulation
Modulation type pulsed
Pulse width 580 µs
Pulse type biphasic
Exposure setup
Exposure source
  • see Mahrour 2005
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 4 V/cm - - - -

Reference articles

  • Mahrour N et al. (2005): In vitro increase of the fluid-phase endocytosis induced by pulsed radiofrequency electromagnetic fields: importance of the electric field component.
  • Laval L et al. (2000): A new in vitro exposure device for the mobile frequency of 900 MHz.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Lucifer Yellow uptake increased under exposure to GSM electromagnetic fields. Chlorpromazine (inhibitor of the clathrin-mediated pathway) and ethanol (inhibitor of receptor-mediated endocytosis/clathrin-dependent pathway), but not Filipin (inhibitor of the caveolin-mediated pathway), inhibited this increase.
The data show that the mechanism affected by the GSM electromagnetic field involves vesicles that detach from the cell membrane, mainly by clathrin-coated vesicles.

Study character:

Study funded by

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