中文摘要：

目的 评价SNL大鼠鞘内注射KB-R7943的镇痛作用，并探讨其可能的机制。方法 选取成年雄性SD大鼠（180～220 g），建立SNL模型，通过测定机械痛阈选取SNL模型建立成功的大鼠，采用免疫荧光检测其手术侧L4～6脊髓背角钠钙交换蛋白（sodium calcium exchanger，NCX）定位情况；成年雄性SD大鼠进行鞘内置管，置管成功后1周，制作SNL模型，于SNL模型建立的第7天给予鞘内注射不同剂量（5 μg、10 μg、20 μg）KB-R7943以及1% DMSO对照溶剂，通过行为学检测其鞘内注射后引起的机械痛阈和热痛阈变化；记录成年雄性SD大鼠脊髓背角C纤维诱发电位，给予坐骨神经强直电刺激诱发C纤维电位长时程增强（long-term potentiation，LTP），局部脊髓表面给予KB-R7943以及1% DMSO对照溶剂，记录C纤维电位ＬＴＰ的幅度变化。结果 NCX表达在大鼠L4～6脊髓背角浅层的C纤维投射区内。SNL大鼠在术后第7天给予鞘内注射NCX反向转运抑制剂KB-R7943，KB-R7943注射组大鼠手术侧足底的机械痛阈及热痛阈均高于溶剂组（P＜0.05），其抑制作用与剂量呈正相关。大鼠诱发脊髓C纤维电位LTP后，给予局部孵育KB-R7943后可降低C纤维电位幅度，单纯给予溶剂不会影响C纤维电位幅度。结论 SNL大鼠鞘内注射KB-R7943具有剂量依赖性的抗神经病理性疼痛作用，其机制与抑制大鼠脊髓背角内的NCX反向转运功能，并抑制脊髓背角C纤维诱发电位的长时程增强有关。

英文摘要：

Objective To evaluate the analgesic action of intrathecal injection of KB-R7943 in SNL rats, and explore the possible mechanism of analgesia. Methods Male Sprague-Dawley rats（180-220 g）were randomly assigned to four groups, treated with a subarachnoid catheter and subjected to SNL surgery. On day 7 after surgery, the groups received intrathecal injection of solvent or KB-R7943 in doses of 5,10 or 20 μg. Behavioral tests were used to detect changes in mechanical pain threshold and thermal pain threshold. In addition, expression of the sodium-calcium exchanger protein （NCX） on the operation side of the L4-6 spinal dorsal horn was measured using immunofluorescence, and spinal dorsal horn C fiber-evoked potentials were measured. Tetanic stimulation was used to induce long-term potentiation of the C fiber, and changes in C fiber potential amplitude were recorded after applying KB-R7943 or control solvent to the surface of the local spinal cord. Results NCX was expressed on the C fiber projection area of the L4-6 spinal dorsal horn. Intrathecal injection of NCX inhibitor KB-R7943 significantly increased the threshold of mechanical and thermal pain（P〈0.05）,and these effects positively correlated with KB-R7943 dose. KB-R7943 also reduced the potential amplitude of the C fiber observed after tetanic stimulation. Conclusions Intrathecal injection of KB-R7943 produces a dose-dependent analgesic effect in SNL rats. This effect may involve inhibition of the reverse transfer function of NCX in the spinal dorsal horn, as well as reduction in long-term potentiation of C fiber-evoked potential in the spinal dorsal horn.