针刺对慢性炎症局部的镇痛作用

已为大量的临床和实验观察所证明。我们也以佐剂性关节炎大鼠的炎症性疼痛为模型

证实了针刺对炎症局部具有明显的镇痛效果。针后

实验动物的中枢神经系统组织内的脑啡肽含量明显增加

说明针刺可能是通过提高体内的内源性吗啡样物质(MLS)含量

兴奋相应的受体而发生镇痛作用的。但针刺与某些兴奋吗啡样受体的镇痛药物不同

它可能是一种多元性自我调节的过程

除提高Sixty seven rats

weighting from 150 to 200g

were divided into 5 groups:blank control (?)roup

arthritic group

arthritic with acupuncture group

fentanyl+droperidol (FD) group and FD with acupuncture group.Except the normal control all the rats were administcred with complete Freund's adjuvant

then arthritis occurred.The arthritic rats in the acupuneture group were given by electro-acupuncture at“Huantiao”points bilaterally lasting 20 minutes every days for 5 days.After the last stimulation of needling

they were blooded. In the FD group

fentanyl 10μg/kg and dropevidol 0.5mg/kg were given to each rat.15 minutes later

they were tested and cAMP content of plasma were determined by radioimmunoassay method.Results showed that the content of cAMP was at 56.4±14.4pmol/ml in the normal control and 47.3±15.4pmol/ml in the arthritic group.There was no significant difference between these two groups statistically.But it was as higher as 124.4±57pmol/ml of cAMP in the acupuncture group.A comparison was made among these groups (p<0.001).Another series study showed that no any obvious change of the cAMP content could be found in the FD group.The level of cAMP increased markedly in the FD with acupuncture group (P<0.001).Data obtained from our experiment showes that not only pain threshold of the animals but also the content of cAMP in the plasma increased after needling.The fentanyl and droperidol can increase the pain threshold obviously

but there is no influence on the level of cAMP.If FD combines with acupuncture application

the cAMP content still rise after needling.The results above mentioned suggests that cAMP could play an important role in the pain sensory regulation by acupuncture.