100Hz电针促进吗啡依赖和戒断大鼠脊髓强啡肽的释放

100Hz ELECTROACUPUNCTURE INCREASED THE RELEASE OF SPINAL CORD DYNORPHIN IN MORPHINE DEPENDENT AND WITHDRAWAL RATS

目的：研究在吗啡依赖和戒断大鼠１００Ｈｚ电针是否仍有镇痛作用，该作用是否仍由脊髓强啡肽通过κ受体介导。方法：测定辐射热甩尾阈（ＴＦＬ）作为痛阈。结果：（１）给大鼠皮下注射递增量吗啡８天造成大鼠对吗啡的依赖。这时给以１００Ｈｚ电针，ＴＦＬ仍有显著升高，此作用可被大剂量纳洛酮翻转（２０ｍｇｋｇ有效，１ｍｇｋｇ无效），提示由κ阿片受体介导；（２）吗啡依赖和戒断大鼠脊髓灌流液中强啡肽放免活性（Ｄｙｎ－ｉｒ）明显降低，１００Ｈｚ电针使之显著回升。结论：在大鼠吗啡依赖和戒断状态下，１００Ｈｚ电针仍能促进Ｄｙｎ的释放发挥镇痛作用。本结果为临床使用１００Ｈｚ电针治疗吗啡戒断综合症提供了理论依据。

The aim of this study was to clarify whether 100Hz electroacupuncture (EA) could induce analgesic effect in morphine dependent and withdrawal rats, and whether this effect is mediated by dynorphin via κ opioid receptor in spinal cord. (1) Rats were made dependent on morphine by morphine injections b.i.d. for 8 consecutive days. The rats were then given 100Hz EA stimulation for 30 min. A marked increase in tail flick latency (TFL) was observed. This effect of 100Hz EA could be blocked by naloxone at 20mgkg, but not at 1mgkg dose, suggesting that 100Hz EA induced analgesia observed in morphine dependentwithdrawal rats is mediated by κ opioid receptors; (2) A significant decresase of the concentration of dynorphin immunoreactivity ( ir) in the spinal perfusate (CSF) was observed in morphine dependent and withdrawal rats, that could be brought back to normal level by 100Hz EA. The results show that in morphine dependent and withdrawal rats 100Hz EA can also induce dynorphin release in the spinal cord to produce analgesia as in normal rats. The findings of the present study provide new evidence supporting the clinical use of 100Hz EA for treating morphine withdrawal syndrome. Supported by NNSF of China and NIDA, USA.