Auricular Acupuncture for Pain and Inflammation

Auricular acupuncture (AA) is a special acupuncture treatment system that can be used on its own or in conjunction with other acupuncture treatment systems. Review of the literature showed that AA had been used extensively in treatment of various pain and inflammatory conditions. However, its mechanism of action remained poorly understood, and it was not clear whether the location of stimulation at the auricle was important for its efficacy. By using rat models of experimentally induced inflammation, we explored the issue of acupuncture point location specificity and tested the roles of opioid and muscarinic receptors in mediating the anti-inflammatory effects of AA. We also compared the efficacy of AA with that of electroacupuncture at meridian points. We found that there was no strict functional topography for AA, although certain regions appeared to produce more consistent anti-inflammatory effects. Muscarinic receptors played an important role in both the analgesic and antiedematous actions of AA, whereas opioid receptors were only involved in the analgesic action. We also found that the efficacy of both AA and electroacupuncture at meridian points were comparable. Our findings suggest that the action of AA may be mediated by a unique mechanism and it should be used in conjunction with meridian acupuncture to enhance the efficacy of acupuncture treatment.