Abstract
Millimeter wave treatment (MMWT) is based on the systemic biological effects that develop following local skin exposure to low power electromagnetic waves in the millimeter range. In the present set of experiments, the hypoalgesic effect of this treatment was analyzed in mice. The murine nose area was exposed to MMW of “therapeutic” frequencies: 42.25, 53.57, and 61.22 GHz. MMWT‐induced hypoalgesia was shown to be frequency dependent in two experimental models: (1) the cold water tail‐flick test (chronic non‐neuropathic pain), and (2) the wire surface test (chronic neuropathic pain following unilateral constriction injury to the sciatic nerve). Maximum hypoalgesic effect was obtained when the frequency was 61.22 GHz. Other exposure parameters were: incident power density = 13.3 mW/cm^2^, duration of each exposure = 15 min. Involvement of δ and κ endogenous opioids in the MMWT‐induced hypoalgesia was demonstrated using selective blockers of δ‐ and κ‐opioid receptors and the direct ELISA measurement of endogenous opioids in CNS tissue. Possible mechanisms of the effect and the perspectives of the clinical application of MMWT are discussed. Bioelectromagnetics 29:284–295, 2008. © 2007 Wiley‐Liss, Inc.