甲醛诱导的伤害性感受过程中神经元型和诱导型一氧化氮合酶表达的上调

Up-regulation of both neuronal and inducible nitric oxide synthase during formalin-induced nociception

目的：观察大鼠甲醛炎性痛过程中，脊髓神经元型一氧化氮合酶（nNOS）和诱导型一氧化氮合酶（iNOS）表达的变化。方法：免疫组织化学方法观察SD大鼠脊髓nNOS和iNOS的表达。结果：注射甲醛后1、12、24、48h和72h，大鼠腰5脊髓后角浅层nNOS和iNOS表达均上调，且其上调趋势与大鼠甲醛实验中的痛行为反应相一致。脊髓后角深层和后角周围白质区也可见一些iNOS免疫反应阳性细胞，其表达变化趋势与上述浅层的免疫阳性细胞的表达变化相似。结论：nNOS和iNOS共同参与了甲醛诱导的伤害性感受过程。

Objective= To observe changes in the expression of neuronal nitric oxide synthase （nNOS） and inducible nitric oxide synthase （iNOS） in the spinal cord during formalin-induced nociception. Methods： The expression of nNOS and iNOS in the spinal cord was observed using immunohistochemistry in SD rats. Results： The expression of both nNOS and iNOS in the superficial laminae of dorsal horn of the fifth lumbar segment （L5） of the spinal cord up-regulated at time point of 1 h as well as 12, 24, 48 h and 72 h after formalin injection. The pattern of up-regulation was in parallel with changing in pain-related behavioral responses of the rats in formalin test. In the deeper layers of the spinal dorsal horn and the white matter surrounding the dorsal horn, there also existed some iNOS immunoreactive cells which showed similar pattern in immunoreativity with the above superficial immunoreactive cells. Conclusion： The results suggest that both nNOS and iNOS are involved in the formalin-induced nociception.