To study the thermal and cardiovascular responses of conscious (restraint) versus ketamine anesthetized rats exposed to 2.8 GHz radiofrequency irradiation. The experiments were conducted under the same conditions as in a previous study of Fischer 344 rats (publication 2242).
|Distance between exposed object and exposure source||150 cm|
|Chamber||The Eccosorb RF-shielded anechoic chamber was maintained at 27 ± 0.5°C and 20 ± 5% humidity.|
|Setup||A rat was restrained in a vented Plexiglas cage and placed within the exposure chamber on a stand made of 2-inch thick high density Styrofoam. The rat was positioned along the boresight and exposed in H-orientation (left lateral exposure, long axis of the body parallel to the magnetic field).|
|Additional info||The exposure was interrupted when the colonic temperature had increased to 39.5°C. It was resumed when the temperature had returned to 38.5°C and was continued until it increased to 39.5°C again. This procedure was repeated for three cycles after which anaesthesia was provided by an i.m. injection of ketamine. After anaesthesia was sufficient, the start sequence and three additional cycles were completed. The rise and recovery times were 4.6 ± 0.2 min and 14.2 ± 1.2 min for unanaesthetized animals and 11.5 ± 1.1 min and 16.4 ± 1.4 min for anaesthetized animals, respectively.|
The time required for the 1°C temperature increase was significantly longer in the anesthetized animals. During exposure, heart rate increased significantly both with and without anesthesia, while mean arterial blood pressure increased only when the animals were unanesthetized. The heart rate increase in the anesthetized state contrasts with a lack of change in a previous study of Fischer rats (publication 2242). This difference between anesthetized Sprague-Dawley and Fischer rats should be considered when comparing cardiovascular results obtained from these two strains of rats.