Analgesic effect of simultaneous exposure to infrared laser radiation and μT magnetic field in rats

摘要

The aim of the experiment was to estimate the effect of repeated simultaneous exposures to infrared laser radiation and uT variable magnetic field used in magnetostimulation on pain perception in rats, as well as the involvement of endogenous opioid system in the mechanism of this effect. In experimental group clean-shaven scull of male Wistar rats placed individually in a specially designed plastic chamber were simultaneously exposed to infrared laser radiation (wavelength - 855 nm, mean power - 4,1 mW, energy density - 30 J/cm~2) and variable magnetic field of saw-like shape of impulse, at a frequency of basic impulse 180-195 Hz and mean induction value of 120 μT generated by magneto-laser applicator of device for magnetostimulation Viofor JPS (Med & Life, Poland) 12 minutes daily for 2 periods of 5 consecutive days, with 2 days-lasting break between them, while control animals were sham-exposed. The pain perception was determined by means of "hot plate" test on the basis of calculated analgesic index. As a result of repeated exposures a significant increase in analgesic index persisting also till 14th day after the end of a cycle of exposures was observed. This analgesic effect was inhibited by prior i.p. injection of opioid antagonist - Naloxone.