Abstract
After 0.1ml of 2% carrageenin s. c. injection into a rat's pow, He-Ne laser with 632.8nm of wave length and 8.5 mW of power was continuously irradiated on the circular area of 7 mmo on the pow and its analgetic effect was examined by the Randall-Sellito method. Although the carrageenin injection caused a 70% decrease in the pain threshold 3hr later, it recover the control level just after 6 or 8min irradiation but not 2 or 4min irradiation of laser. While the inflamed rat's pow even 27 hr after the carrageenin injection, no differance in the pain threshold between them was recorded even 24hr after the 6 min laser irradiation.
These result indicate that the laser irradiation exerts an analgetic effect on the inflamed pow and effect lasts for at least 24hr.
