Does nitric oxide mediate circulatory failure induced by 35-GHz microwave heating?
The purpose of this study was to determine whether nitric oxide (NO) contributes to the hypotensive state induced by exposure to radiofrequency radiation of millimeter-wavelength (MMW). This was accomplished using a synthetic analogue of L-arginine, N omega-nitro-L-arginine methyl ester (L-NAME), to competitively inhibit NO synthesis. Ketamine-anesthetized rats were instrumented for the measurement of arterial blood pressure, ECG, and temperature at five sites. Animals were exposed to 35-GHz radiofrequency radiation until mean arterial pressure (MAP) decreased to 75 mmHg. MMW exposure was then halted and either saline or L-NAME (1, 2.5, 5, or 10 mg/kg) was administered; each rat received only one dose. Following irradiation, L-NAME at each dose produced a peak increase in MAP that was smaller than that produced by the same dose of L-NAME in nonirradiated rats. There was no difference in post-MMW survival times between L-NAME-and saline-treated rats. These results indicate that bolus administration of L-NAME does not reverse hypotension induced by 35-GHz microwave heating, suggesting that excess levels of NO do not mediate this form of circulatory failure.
Ryan
K L
KL
Department of Biology, Trinity University, San Antonio, Texas 78212, USA.
Frei
M R
MR
Berger
R E
RE
Jauchem
J R
JR
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000528:radiation effects; D001831:Body Temperature / Q000187:drug effects / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000187:drug effects / Q000528:radiation effects; D006339:Heart Rate / Q000187:drug effects / Q000528:radiation effects; D006439:Hemodynamics / Q000187:drug effects / Q000528:radiation effects; D006358:Hot Temperature; D008297:Male; D008872:Microwaves; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values
D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester