Study type: Medical/biological study (experimental study)

Low frequency amplitude modulated microwave fields change calcium efflux rates from synaptosomes. med./bio.

Published in: Bioelectromagnetics 1982; 3 (3): 309-322

Aim of study (acc. to editor)

To investigate the effects of a 450 MHz (16 Hz AM, 60 Hz AM, or CW) microwave exposure in vitro on the calcium efflux in rat synaptosomes.

Background/further details

Electron microscopy was used to determinate the integrity of the synaptosome preparation. To examine the calcium efflux during exposure a continuous perfusion technique was used.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 450 MHz
Modulation type: CW
Exposure duration: continuous for 10 min
Exposure 2: 450 MHz
Modulation type: AM
Exposure duration: continuous for 10 min
Exposure 3: 450 MHz
Modulation type: AM
Exposure duration: continuous for 10 min

Exposure 1

Main characteristics
Frequency 450 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 10 min
Modulation
Modulation type CW
Exposure setup
Exposure source
Exposure room A hemispheric plastic Millipore filter holder having a base diameter of 25 mm and a volume of 1 cm³ was mounted on a Plexiglas platform in the center of a Crawford cell with the filter 5 cm below the top of the chamber.
Setup The filter was half-filled with temperature controlled solution at 31 °C delivered from a syringe at 1 ml/min throughout the perfusion. Perfusate-collecting vials were placed in a cardboard box with 6-mm walls on the septum and were moved manually one position every minute.
Additional info Duplicate samples were prepared from the same incubation; one served as control and the other one was exposed to MW fields during perfusion. Both syringes were mounted on the same pump, and temperature was maintained by the same circulator. The effect of temperature alone was studied by perfusion at 25, 31, 33, and 35 °C. For stimulation by calcium, a concentrated CaCl2 solution was injected at a rate of 10µl/min for 5 min. Choline chloride injection served as control.
Parameters
Measurand Value Type Method Mass Remarks
power density 0.5 mW/cm² peak value measured - -
electric field strength 43 V/m peak value measured - in air

Exposure 2

Main characteristics
Frequency 450 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 10 min
Modulation
Modulation type AM
Modulation frequency 16 Hz
Modulation depth 75 %
Additional info

sinusoidal

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power density 0.5 mW/cm² peak value measured - -

Exposure 3

Main characteristics
Frequency 450 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 10 min
Modulation
Modulation type AM
Modulation frequency 60 Hz
Modulation depth 75 %
Additional info

sinusoidal

Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power density 0.5 mW/cm² peak value measured - -

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The calcium efflux was increased by the 450 MHz 16 Hz AM modulated microwave exposure, whereas exposure to CW or 60 Hz AM modulated fields did not lead to similar changes.

Study character:

Study funded by

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