一般认为

伤害性刺激的一级传入纤维主要为含P物质(SP)的C类纤维

其胞体是脊神经节内的B型细胞。关于C类纤维在电针信息传入中的作用

至今仍存在争议。众多资料表明

辣椒素对脊神经The present paper is designed to investigate the variation of pain threshold and electroacupuncture analgesia of rat

and to observe the immunohistochemical changes in spinal ganglion and dorsal horn of lumber and sacral segment of spinal cord after extradural administration of capsaicin (100μg/rat). It was found: 1. Obvious decrease of pain threshold 60 mins after injection of capsaicin

and the pain threshold restored nearly to the level of pre-treatment at 90 mins of post-treatment of capsaicin. 2. Apparent elevation of pain threshold on 1st-15th day after injection of capsaicin. 3. The efficiency of electroacupuncture analgesia 7th day after injection of capsaicin was obviously weaker than that of pre-treatment of drug and that of solvents treatment in the animals of control group. 4. The SP-LI

ENK-LI and FRAP were all weakened in dorsal horn of spinal cord 1h after capsaicin treatment. However

on the 7th day

with the exception of decrease of SP-LI and FRAP

the ENK-LI in dorsal horn was strengthened and the activity of FRAP in spinalganglionic cells of B type disappeared. The foregoing results indicated that the metabolism and function of C fibers of primary afferent especially the SP containing nerve and those of ENK-containing neurons could be influenced by the extradural injection of capsaicin. And the primary afferent C fiber (inclunding the SP containing nerve) may play important roles in the imput of the informations of pain

and needling

as well as in the acupuncture analgesia.