[Study on the analgesic effect of acupuncture with opioid receptors agonist in induced arthritic rats]

Our previous study demonstrated that acupuncture increased pain threshold of the body, especially in the inflammatory area. Because acupuncture can promote the release of enkephalin in the brain, it is possible that analgesic effect of acupuncture could be further strengthened by administration of fentanylan opioid receptor's agonist and droperidol-dopamine receptor's agonist at same time. In present study arthritic rats induced by freund's complete adjuvant were divided into two groups. All of them received electro-acupuncture on bilateral "Hung-Tiao" points for 15 minutes. The first group animals were also given with common dose of fenanyl 10 micrograms/kg and droperidol 0.5 mg/kg by intraperitoneal injection. Pain threshold increased very soon after needling and drugs given. The analgesic effect lasted as long as 180 minutes. There is a statistical significant difference between this common dose group and acupuncture control group which only kept analgesic effect 90 minutes, P less than 0.01. When only 1/5 dose of these drugs with acupuncture was applied to arthritic rats, not only the pain threshold reached to 180 + 3% (P less than 0.01), but also the analgesic effect persisted as long as 120 minutes (P less than 0.01). The results from mentioned above suggested that if a small dose of drug is no effect in usual treatment, it could still play a role and reduce the pharmacological side effect by way of combining acupuncture application.