Abstract
This study was scheduled to investigate the effect of low power He-Ne laser (λ=632.8 nm, 8.5mW) on the sympathetic nerve activity and pain sensory nerve.
Five-minute irradiation of the laser beam was performed on the meeting point (Li4, Hoku) of ten male volunteers ( group G) and on the shousanli (Li10) of 13 male volunteers (group T). The skin temperature and pain threshold were measured at the meeting point of the irradiated arm by using a pain-threshold-meter (UDH104, Unique Medical Co., LTD, Tokyo, Japan) before, immediately after and 30 minutes after irradiation.
In group G, the skin temperature immediately and 30 minutes after irradiation elevated by 0.8 and 0.4°C, and pain threshold by 0.3 and 0.5°C, respectively. In group T, the skin temperature immediately and 30 minutes after irradiation rose by 0.9 and 0.4°C, but pain threshold declined by 0.2 and 0.4°C, respectively.
These results suggest that a laser irradiation may act in different fashions on the sympathetic nerve system and on the descending inhibitory system.
