To examine effects of the nonselective α-adrenoceptor antagonist phentolamine (10 mg/kg), the α1-adrenoceptor antagonist prazosin (5 mg/kg), and the β1-adrenoceptor antagonist metoprolol (2 mg/kg) on heart rate, mean arterial blood pressure, respiratory rate, and localized body temperature changes that occur during lethal exposure of anesthetized rats to 2450-MHz microwave radiation. Control animals (N = 6) received a saline solution. The purpose of the study was not to obtain a dose-response curve for each drug. Rather, this was a screening study to determine if selected doses of particular agents could effect responses to microwaves.
Details of exposure condition are given in the following article: Bara M, Guiet-Bara A, Durlach J. Monovalent cations transfer through isolated human amnion: A new pharmacological model. Meth Find Exp Clin Pharmacol 1985, 7: 209-16.
There were no significant differences in lethal temperatures, survival times, or rates of temperature change among the different groups. Heart rate and blood pressure changes were similar to those that occur during environmental heat stress. The lack of significant effects of nonselective α-adrenoceptor antagonist phentolamine, the α1-adrenoceptor antagonist prazosin, and the β1-adrenoceptor antagonist metoprolol on microwave-induced body temperature changes may suggest that higher doses should have been used.