氯胺酮对辣椒素致敏大鼠的超前镇痛作用

目的:探讨氯胺酮对辣椒素(capsaicin)所致痛过敏(hyperalgesia)的预防作用。方法:将Wister大鼠64只随机分为四组:辣椒素对照组、50ml氯胺酮+对照组、100μl氯胺酮+对照组、200μl氯胺酮+对照组。深麻醉下置入硬膜外导管,测定痛阈的变化及脊髓背角(Spinalcorddorsalhorn,SCDH)P物质(substanceP)的改变。结果:与对照组相比,50μl组SP-L1的相对密度有降低趋势,100μl组、200μl组SP-L1的相对密度则明显降低。结论:痛敏初期,氯胺酮可显著缓解辣椒素所致痛过敏,但不能完全消除痛敏的存在;继发痛敏期,氯胺酮的抗痛敏效应与期剂量、作用时间密切相关。

The preemptive analgesia of ketamine on hyperalgesia in rats induced by capsaicin

Objective To analyse the pre emptive analgesia of ketamine on hyperalgesia inrats in duced by capsaicin.Method64Wistar were divided into four groups:control,group50μl(of ketamine),group100μl and group200μl.Catheter placement was performed by using sterile technique.The values of pain threshold (PT)and the changes of substant P at the dorsal horn(L5)were measured.Re sults In contrast with control,the changes of PT and the densities of SP-LI at laminaeⅠ-Ⅱare significant,but the values of PT are still under the normal level.Conclusion The ketamine would not avoid the nociceptive response of hyperalgesia in the beginning of treatment.But it can significantly reduce the second hyperalgesia in all experimental groups.