A lot of work had been done to explore the mechanism of acupuncture anal-gesia (AA), but there have been some important questions to be dclarified. Forcxample, what kind of afferent fiber plays an important role in AA? In orderto solve this question, we applied capsaicin topically on sciatic nerve and usedthe techniques of extracellular recording and nerve trunk recording. A lot of work had been done to explore the mechanism of acupuncture anal-gesia (AA), but there have been some important questions to be dclarified. Forcxample, what kind of afferent fiber plays an important role in AA? In orderto solve this question , we applied capsaicin topically on sciatic nerve and used the techniques of extracellular recording and nerve trunk recording.