The behavioral observation of nociceptive responses were carried out immediately after formalin administration by examining the total time used for licking and biting towards the injected hindpaw by rats , and then , one hour later after formalin injection , rats were killed for immunocytochemical procedures for fos expression in the dorsal horn R ,或mgi叭:的拮抗剂c尸ccoet / mpe尸。以单纯注射formalin侧背角的fos表达( fli神经元)作为对照,对同一脊髓双侧背角的fl工进行观察、记数并进行比较和统计学处理。