title: Platelet-activating factor does not mediate circulatory failure induced by 35-GHz microwave heating.
abstract: Sustained whole-body exposure of anesthetized rats to 35-GHz radiofrequency radiation produces localized hyperthermia and hypotension, leading to circulatory failure and death. The physiological mechanism underlying the induction of circulatory failure by 35-GHz microwave (MW) heating is currently unknown. The purpose of this study was to determine whether platelet-activating factor (PAF) contributes to the hypotensive state induced by MW heating. Ketamine-anesthetized rats were instrumented for the measurement of arterial blood pressure, ECG and temperature at five sites. Administration of the PAF-receptor antagonist WEB 2086 (0.5 or 5 mg/kg) following the induction of circulatory failure (defined as a decrease in mean arterial blood pressure to 75 mmHg) failed to reverse the hypotension induced by MW heating and consequently did not alter the subsequent survival time. Furthermore, pretreatment with WEB 2086 at either dose did not alter subsequent mean arterial blood pressure, temperature responses to MW heating or survival time. Finally, MW heating did not alter either blood PAF levels or serum or lung PAF acetylhydrolase levels. Taken together, these results demonstrate that PAF does not mediate the hypotension induced by 35-GHz MW heating.
authors.affiliation: Air Force Research Laboratory, Directed Energy Bioeffects Division, Radio Frequency Radiation Branch, Brooks Air Force Base, San Antonio, Texas, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Ryan
authors.forename: J R
authors.initials: JR
authors.lastname: Jauchem
authors.forename: M R
authors.initials: MR
authors.lastname: Tehrany
authors.forename: H L
authors.initials: HL
authors.lastname: Boyle
mesh_terms: D000818:Animals; D001381:Azepines / Q000494:pharmacology; D005334:Fever / Q000209:etiology* / Q000517:prevention & control; D006439:Hemodynamics / Q000187:drug effects; D007022:Hypotension / Q000209:etiology*; D008297:Male; D008872:Microwaves / Q000009:adverse effects*; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014230:Triazoles / Q000494:pharmacology
chemical_list: D001381:Azepines; D010972:Platelet Activating Factor; D014230:Triazoles; C052518:WEB 2086