CGRP受体拮抗剂CGRP8-37对甲醛炎性痛大鼠自发痛反应及脊髓后角NOS表达和NO含量的影响

目的:探讨CGRP受体拮抗剂CGRP8-37对甲醛炎性痛大鼠自发痛反应及脊髓后角NOS表达和NO含量的影响.方法:大鼠足底注射甲醛制造炎性痛模型;计数缩足反射次数反映自发痛程度;NADPH-d组织化学法观察脊髓后角NOS表达;硝酸还原酶法测定NO-3/NO-2含量以反映NO含量.结果:足底注射甲醛后,动物出现自发痛反应行为.足底注射甲醛后24 h,双侧脊髓后角NOS表达及NO含量明显增加.预先鞘内注射CGRP8-37可使甲醛诱导的自发性缩足反射次数明显减少,并可明显抑制甲醛炎性痛诱导的脊髓后角NOS表达及NO含量的增加.结论:甲醛炎性痛时,脊髓后角CGRP受体激活可促进NOS活性表达及NO的产生.

Effect of CGRP receptor antagonist CGRP8-37 on nociceptive response, NOS expression and NO content in the dorsal horn of spinal cord during formalin-induced inflammatory pain in rats

Aim: To study the effect of CGRP receptor antagonist CGRP8-37 on nociceptive response and expression of nitric oxide synthase (NOS) and content of nitric oxide(NO) in the dorsal horn of the spinal cord of rats during formalin-induced inflammatory pain. Methods: Using formalin injection into right hind paw induced inflammatory pain. Counting the times of flinching reflex was used to observe the degree of spontaneous pain. NADPH-d histochemistry was used to observe the changes of NOS expression. The content of NO was observed by measuring the contents of nitrate/nitrite(NO~-_3/ NO~-_2). Results: spontaneous pain behavioral was elicited by formalin injection.The NOS expression and NO content significantly increased in the spinal cord at 24h after formalin injection. Intrathecal injection of CGRP8-37 could significantly inhibit the response of spontaneous pain and the increases of NOS expression and NO content induced by formalin injection. Conclusion: The activation of CGRP receptors enhances NOS expression and NO production in the dorsal horn of the spinal cord during formalin-induced inflammatory pain.