摘要：
Objective: The present study was performed to observe the expression of Nogo-A, substance P (SP) and calcitonin gene-related peptide (CGRP) in periaqueductal gray (PAG) of hyperalgesia rats , and to investigate the role of Nogo-A in pain modulation, and the relationship with CGRP , SP and endogenous opioid system. Methods: 32 male SD rats were randomly divided into four groups: control group received intra-PAG injection of 0.9 % saline (1 μl); Model group, morphine group and naloxone group received unilateral hindpaw hypodermic injection of 1 % formalin (0.1 ml) to prepare pain model, then received intra-PAG injection of 0.9 % saline 1 ul, morphine 1 ul or naloxone 1 μl respectively 3 days later. After 60 minutes , the PAG area of rats were obtained, the expression of Nogo-A, SP and CGRP in PAG of rats in each group were observed and measured by immunohistochemical method. Results: The expression of Nogo-A immunoreactive neuron of model group was obviously reduced than that of control group (P<0.01), but CGRP and SP was obviously increased (P<0.01); The expression of Nogo-A immunoreactive neuron of morphine group was obviously increased than compared with model group(P<0.01), but CGRP and SP was obviously reduced (P < 0.05); The expression of Nogo-A immunoreactive neuron in naloxone group was obviously reduced than that in model group (P<0.05 ), but CGRP and SP was obviously increased (P<0.05). Conclusion: (1) The expression of Nogo-A immunoreactive neuron of model group was obviously reduced than that of control group, but the CGRP and SP were obviously increased . (2) The expression of Nogo-A immunoreactive neuron was obviously increased by opioid system in PAG, but the CGRP and SP were reduced.%目的:用脑内核团微量注射和免疫组化等方法,观察大鼠中脑导水管周围灰质( periaqueductal gray,PAG)内“勿动蛋白”-A(Nogo-A)、P物质(substanceP,SP)和降钙素基因相关肽(calcitoningene-related peptide,CGRP)表达的变化,研究探讨Nogo-A在痛觉调制过程中的角色,以及它在大鼠PAG内与CGRP、SP和内源性阿片系统在痛觉调制过程中的相互作用.方法:选用雄性SD大鼠32只,随机等分为4组:空白对照组8只,分别向PAG内注射0.9％生理盐水1μl;模型对照组、吗啡组和纳洛酮组各8只,首先单侧后爪掌心皮下注射1％的福尔马林0.1 ml复制炎症痛敏大鼠模型,3d后分别向PAG内注射等量0.9％生理盐水、吗啡或纳洛酮各1 μl,60 min后取大鼠大脑PAG区脑组织,采用免疫组化法观测各组大鼠PAG内Nogo-A、SP和CGRP免疫反应阳性神经元的表达差异.结果:与空白对照组比较,模型对照组大鼠PAG内Nogo-A的表达量显著降低(P＜0.01),CGRP及SP显著增高(P＜0.01)；与模型对照组比较,吗啡组大鼠PAG内Nogo-A的表达量显著增高(P＜0.01),CGRP及SP显著降低(P＜0.05),而纳洛酮组PAG内Nogo-A的表达量显著降低(P＜0.05),CGRP及SP显著增高(P＜0.05).结论:(1)炎症痛敏大鼠PAG内Nogo-A的表达量比正常降低,而CGRP及SP显著增高；(2)阿片肽可增加PAG内Nogo-A的表达,并降低CGRP及SP的表达.
