Contralateral electroacupuncture pretreatment suppresses carrageenan-induced inflammatory pain via the opioid-mu receptor.
Acupuncture has been used to treat various clinical diseases in Eastern medicine. To investigate the analgesic effect of electroacupuncture (EA) pretreatment on carrageenan-induced inflammatory pain, we studied on the effect of EA parameters on an animal model of acute arthritic pain. Pretreatment with 1 mA, 10 Hz EA prior to carrageenan injection under halothane anesthesia suppressed carrageenan-induced pain. Interestingly, EA stimulation of the 'Zu-San-Li' (ST36) acupuncture point (1 mA, 10 Hz) contralateral to the site of the carrageenan injection in the rat synovial cavity produced significantly greater improvement of the weight-bearing force compared with EA stimulation of the 'San-Yin-Jiao' acupuncture point. To determine how ST36 EA treatment suppresses carrageenan-induced inflammatory pain, we examined the effect of a mu opioid receptor antagonist on ST36 EA-induced analgesia. The selective antagonist of the mu opioid receptor (OR) significantly suppressed contralateral ST36 EA-induced analgesia against carrageenan-induced inflammation. These results suggested that the analgesic effect mediated by the mu OR during low-frequency contralateral EA pretreatment has an anti-nociceptive action against inflammatory pain and that it may provide a potential strategy to treat inflammatory arthritic pain.
Yang
Eun Jin
EJ
Department of Standard Research, Korea Institute of Oriental Medicine, 461-24, Jeonmin-dong, Yuseong-gu, Taejon, 305-811, Korea.
Koo
Sung Tae
ST
Kim
Yoo Sung
YS
Lee
Ji Eun
JE
Hwang
Hye Suk
HS
Lee
Myeong Soo
MS
Choi
Sun-Mi
SM
D015669:Acupuncture Points; D000818:Animals; D002351:Carrageenan; D004195:Disease Models, Animal; D015671:Electroacupuncture / Q000379:methods*; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism / Q000628:therapy*; D007270:Injections, Intra-Articular; D008297:Male; D010146:Pain / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control*; D010147:Pain Measurement; D017288:Pain Threshold; D051381:Rats; D017207:Rats, Sprague-Dawley; D017450:Receptors, Opioid, mu / Q000378:metabolism*; D016474:Weight-Bearing / Q000502:physiology
D017450:Receptors, Opioid, mu; D002351:Carrageenan