氯胺酮的外周镇痛作用及其机制的初步研究

The peripheral analgesic effect of ketamine and its mechanism

目的 观察氯胺酮外周局部给药的镇痛作用 ,并初步探讨其可能的机制。方法 以热板法研究小鼠双后肢跖部皮下注射微量氯胺酮的镇痛效应 ,并给以纳洛酮研究此效应与阿片受体的关系。结果 小鼠双后肢跖部皮下注射 36mmol/L氯胺酮 5 μl后 15s及 5min时痛阈明显延长 (P <0 .0 5 ) ,双后肢跖部皮下注射微量阿片受体阻断剂纳洛酮可拮抗氯胺酮的局部镇痛效应 ,而全身应用等量纳洛酮对氯胺酮的效应无明显影响。结论 氯胺酮的镇痛效应除与中枢有关外 ,同时存在外周机制 。

s:Objective To examine the peripheral analgesic effect of ketamine and to explore its mechanism. Methods The analgesic effect of topical administration of small-dose ketamine was studied by using hot-plate test in mice. Naloxone was employed to study its mechanism. Results 15 sec and 5 min after subcutaneous injection of ketamine (36 mmol/L,5 μl) into both hindpaws, the threshold of pain increased significantly (P<0.05). When naloxone (0.04%,5 μl) was injected subcutaneously into the same area 3 min before the application of ketamine, the analgesic effect of ketamine was antagonized. However, when the same dose of naloxone was intraperitoneally injected, no apparent effect on the analgesia was produced. Conclusion Ketamine acts on peripheral nociceptors to produce analgesia, which may be related to the activity of peripheral opioid receptors.