Study type: Medical/biological study (experimental study)

Increase in nitric oxide and cyclic GMP of rat cerebellum by radio frequency burst-type electromagnetic field radiation. med./bio.

Published in: J Physiol 1993; 461: 513-524

Aim of study (acc. to author)

The purpose of this in vitro study was to determine whether radiofrequency burst-type electromagnetic fields may facilitate NO synthesis, activate guanylate cyclase and increase the production of cyclic GMP.

Background/further details

Rat cerebellum supernatant was used. Recently, it has been established, that guanylate cyclase is activated by a catalytic action of NO synthase (NO synthase is prominently localized in the cerebellum tissues).
In an in vivo study (using the arterioles of the frog web) the relation of NO synthesis with the vasodilatory effect was studied.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 10 MHz
Modulation type: pulsed
Exposure duration: 15 min and 30 min
Exposure 2: 10 MHz
Modulation type: pulsed
Exposure duration: 15 min and 30 min

Exposure 1

Main characteristics
Frequency 10 MHz
Type
Waveform
Exposure duration 15 min and 30 min
Modulation
Modulation type pulsed
Duty cycle 50 %
Repetition frequency 10 kHz
Exposure setup
Exposure source
Distance between exposed object and exposure source 0.0075 m
Setup circular coil with inner diamter of 13 mm, outer diameter of 18 mm and 10 turns; test tube in the center of the coil
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 790 V/m - cf. remarks - -
magnetic flux density 2.65 µT - cf. remarks - -
cf. remarks - - - - U= 5 V peak-to-peak

Exposure 2

Main characteristics
Frequency 10 MHz
Type
Exposure duration 15 min and 30 min
Additional info volley-typed field
Modulation
Modulation type pulsed
Duty cycle 100 %
Additional info

volley-typed field

Exposure setup
Exposure source
Distance between exposed object and exposure source 0.0075 m
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
cf. remarks - - - - U = 5 V peak-to-peak

Reference articles

  • Miura M et al. (1991): Non-thermal vasodilatation by radio frequency burst-type electromagnetic field radiation in the frog.

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

When the supernatant was incubated with both exogenous L-arginine (NO donor) and NADPH, and irradiated by an radiofrequency burst-type electromagnetic field, the production of cyclic GMP was increased significantly. By contrast, such an effect was not found when the cerebellum supernatant was irradiated by an radiofrequency field volley-type electromagnetic field.
When neither L-arginine nor NADPH were added to the supernatant, the production of cyclic GMP was lowered and the exposure effect was not found.
Incubation with Methylene Blue, a guanylate cyclase inhibitor, lowered the production of cyclic GMP and the exposure effect did not occur. On incubation with a NO synthase inhibitor, the production of cyclic GMP was lowered and the irradiation effect was not observed.
Using electrochemical NO probes, the production of NO in the supernatant was detected. The concentration of NO increased after the onset of the electromagnetic field exposure. The irradiation effect persisted, and reached a maximum after the cessation of the exposure.
The arterioles of the frog web were dilated by the exposure, and this effect was almost completely abolished by the addition of a NO synthase inhibitor. This indicates that exposure activates NO synthase and induces vasodilatation.

Study character:

Study funded by