中文摘要：

目的：观察缺失触液核（CSF-contacting nucleus）对大鼠痛行为及脊髓背角痛相关物质5-羟色胺（5-HT）和c—Fas表达的影响，为触液核参与疼痛调制及机制提供实验依据。方法：成年雄性SD大鼠随机分为正常组（Control），假手术组（Sham），霍乱毒素亚单位B与辣根过氧化酶复合物（CB—HRP）组和毁损触液核组（Damage）。以机械缩足阈值（MWT）和热缩足潜伏期（耶儿）测定大鼠痛行为。免疫荧光法检测脊髓背角5-HT和c—Fos表达，并进行痛行为阈值与物质变化趋势的相关分析。结果：与Control、Sham和CB—HRP组相比，Damage组大鼠MWT和TWL明显降低（P〈0．05）。免疫荧光结果显示，正常大鼠触液核神经元高表达5-HT；Damage组大鼠触液核神经元数量随毁损天数延续逐渐减少，且在给予毁损剂CB—SAP第10天完全消失。与此同时脊髓背角5-HT和c—Fos表达量日趋增加，且与痛行为阈值变化趋势成负相关。结论：CB—SAP能科学可靠靶向毁损触液核，缺失触液核可致大鼠痛行为阈值减低，而脊髓背角5-HT和c—Fos表达量增加。本研究提示触液核参与了疼痛调制，且5-HT和c—Fos在此调制中发挥了重要作用。

英文摘要：

Objective： The changes of pain threshold and expression of 5-hydroxytryptamine（5-HT） and c-Fos in spinal dorsal horn of rats were observed after targetedly damaged the cerebraspinal fluid-contacting nucleus（ CSF-coutacting nucleus） to provide experimental evidence for the mechanism of regulating pain CSF-contacting nucleus involved in. Methods： Male adult SD rats were divided into control, sham, choleratoxin subunit B conjugated with horse-radish peroxidase（CB-HRP） and damage groups randomly. The pain threshold using mechanical withdrawal threshold （MWT） and thermal withdrawal latency （TWE） were recorded and analyzed the expression of 5-HT and c-Fos in spinal dorsal horn. Results： Compared with the control, sham and CB-HRP groups, the MWT and TWL of the damage group were significantly increased （ P 〈 0.05）. The results of immunofluorescence showed that 5-HT was detected in neurons of CSF-contacting nucleus. In the damage group, the number of neurons of CSF-contacting nucleus reduced gradually, and no survived neurons were observed at the 10th day. Meanwhile, both the expression of 5-HT and c-Fos in spinal dorsal horn increased gradually, and negatively correlated with the change of pain threshold. Conclusion： The method of targeted damaging CSF-contacting nucleus by cholera toxin subnit B conjugated with saporin（CB-SAP） is scientific and reliable, and it results in the changes of pain threshold and expression of 5-HT and c-Fos in spinal dorsal horn of rats. This study suggests that CSF-contacting nucleus participate in the regulation of pain, moreover, 5-HT and c-Fos play important roles in this regulation.