Study type: Medical/biological study (experimental study)

Does nitric oxide mediate circulatory failure induced by 35-GHz microwave heating? med./bio.

Published in: Shock 1996; 6 (1): 71-76

Aim of study (acc. to author)

To determine whether nitric oxide (NO) contributes to the hypotensive state induced by exposure to radiofrequency radiation of millimeter-wavelength. To explore this question, a synthetic analogue of L-arginine, Nw-nitro-L-arginine methyl ester (L-NAME), was used to pharmacologically inhibit the synthesis of NO following millimeter wavelength exposure.
(NO is a potent endogenous vasodilator produced from the guanidino nitrogen group of L-arginine by the enzyme nitric oxide synthase (NOS). Under physiological conditions, the release of NO by NOS in vascular endothelial cells dilates blood vessels and, in concert with vasoconstrictor catecholamines, regulates blood vessel diameter, organ blood flow, and blood pressure. Pathological increases in NO release have been shown to mediate hypotensive states and circulatory shock.)

Endpoint

Exposure

Exposure Parameters
Exposure 1: 35 GHz
Modulation type: CW
Exposure duration: until bloodpressure decreased to 75 mmHg: 36.7 ± 0.7 min
  • SAR: 13 mW/g mean (whole body) (determined calorimetrically.)
  • power density: 750 W/m² unspecified

Exposure 1

Main characteristics
Frequency 35 GHz
Type
Charakteristic
Polarization
Exposure duration until bloodpressure decreased to 75 mmHg: 36.7 ± 0.7 min
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 1.1 m
Exposure room RF-shielded anechoic chamber (27°C, 20% humidity), holder consisting of seven 0.5cm Plexiglas rods mounted in a semicircular pattern on 4 cm x 6 cm Plexiglas plates (0.5 cm thick)
Setup The animal was centered along the boresight and exposed in an E-orientation
Parameters
Measurand Value Type Method Mass Remarks
SAR 13 mW/g mean calculated whole body determined calorimetrically.
power density 750 W/m² unspecified measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Acute pharmacological blockade of NO synthesis following the induction of cardiovascular failure by millimeter wavelength exposure does not ameliorate the hypotensive state and is not of survival benefit to the animal, suggesting that excess levels of NO do not mediate this form of circulatory failure.

Study character:

Study funded by

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