左旋紫堇达明对神经病理性疼痛大鼠的镇痛作用及机制研究

建立坐骨神经慢性压迫损伤诱导的大鼠神经病理性疼痛模型(CCI模型)，探讨左旋紫堇达明(levo-corydalmine，l-CDL)对神经病理性疼痛大鼠痛觉敏化和脊髓中枢敏化的影响。Von-frey法检测机械性缩足反射阈值；热痛刺激仪检测热刺激缩足反射潜伏期；免疫印迹法检测大鼠脊髓L4-L6段N-甲基-D-天冬氨酸受体NR1亚基磷酸化水平；免疫荧光法检测脊髓背角降钙素基因相关肽(CGRP)蛋白表达以及c-fos阳性神经元数目。结果显示，l-CDL(7.5，15 30 mg/kg，ig)能够剂量依赖性地改善CCI模型大鼠机械超敏和热痛过敏。l-CDL［15 mg/(kg·d)，5 d，ig］能显著抑制CCI模型大鼠脊髓CGRP，p-NR1，c-fos的高表达，且不发生镇痛耐受现象。表明l-CDL对CCI模型大鼠神经病理性疼痛具有良好的镇痛作用，其镇痛机制与抑制大鼠脊髓中枢敏化相关。

Analgesic effect of levo-corydalmine on neuropathic pain in rats and its mechanism

The aim of the present study was to investigate the effects of levo-corydalmine(l-CDL)on chronic constrictive injury(CCI)-induced neuropathic pain and central sensitization in spinal cord. The mechanical withdrawal threshold in rats was assessed by Von-Frey fibers and the thermal withdrawal latency was assessed by thermal stimulus apparatus. The level of phosphorylated N-methyl-D-aspartic acid receptor 1(NR1)in L4-L6 spinal cord was analyzed by immunoblotting and the expression of calcitonin gene related peptide(CGRP)and c-fos in spinal cord dorsal horn were analyzed by immunofluorescence. Results showed that l-CDL(7. 5, 15, 30 mg/kg, ig)inhibited CCI-induced mechanical allodynia and thermal hyperalgesia in a dose-dependent manner. l-CDL significantly inhibited the up-regulation of p-NR1, c-fos and CGRP in CCI rats without tolerance. In conclusion, l-CDL has a good relieving effect on central sensitization in spinal cord, thus generating outstanding analgesic activity on CCI-induced neuropathic pain.