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.

By: Miura M, Takayama K, Okada J

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

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.

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.

Exposure	Parameters
Exposure 1: 10 MHz Modulation type: pulsed Exposure duration: 15 min and 30 min	electric field strength: 790 V/m magnetic flux density: 2.65 µT U= 5 V _peak-to-peak
Exposure 2: 10 MHz Modulation type: pulsed Exposure duration: 15 min and 30 min	U = 5 V _peak-to-peak

Frequency	10 MHz
Type	electric field magnetic field
Waveform	sinusoidal
Exposure duration	15 min and 30 min

Exposure source	coil(s)
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

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

Frequency	10 MHz
Type	electric field magnetic field
Exposure duration	15 min and 30 min
Additional info	volley-typed field

Exposure source	same setup as exposure 1
Distance between exposed object and exposure source	0.0075 m
Sham exposure	A sham exposure was conducted.

Measurand	Value	Type	Method	Mass	Remarks
cf. remarks	-	-	-	-	U = 5 V _peak-to-peak

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

Exposed system:

cell function: guanylate cyclase activity ([³H]cyclic GMP production from [8-³H]GTP; liquid scintillation counter); NO production (detection by electrochemical NO probe)
effects on the cardiovascular system: arteriolar vasodilatation

Investigated system:

Investigated organ system:

Time of investigation:

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: