ELECTROMAGNETIC MILLIMETER WAVES INCREASE THE DURATION OF ANESTHESIA CAUSED BY KETAMINE AND CHLORAL HYDRATE IN MICE

BALB/c mice were injected ip with either ketamine 80 mg/kg or chloral hydrate 450 mg/kg. Anaesthetized mice were exposed to unmodulated elec tromagnetic millimeter waves at the frequency of 61.22 GHz with a peak specific absorption rate of 420 W/kg and corresponding incident power density of 15 mW/cm(2) for 15 min or sham-exposed. In combination wit h either of the anaesthetics used, mm waves increased the duration of anaesthesia by approximately 50% (p<0.05) in a dose (power)-dependent manner. Sham exposure to mm waves did not affect the sleeping time of mice. Pretreatment of mice with naloxone, an opioid antagonist, did no t change the duration of anaesthesia caused by the corresponding chemi cal agent, but completely blocked or decreased the additional effect o f mm waves. The data in this study indicates that exposure of mice to mm waves in vivo releases endogenous opioids or enhances the activity of opioid signalling pathway.