Abstract
To understand physiological mechanism of acupuncture effectively, it is required to study in bi-directional way, translational approach. As a "from bedside to bench study", we developed an experimental ankle sprain model for persistent pain showing clear acupuncture analgesia based on the widespread clinical usage. The analgesic effect of electroacupuncture (EA) was specific to the acupoint and the effect could not be blocked by systemic injection of opioid antagonists. However, the α-adrenoceptor antagonist phentolamine completely blocked the EA-induced analgesia by intrathecal injection. These data suggest that this analgesic effect is produced by applying EA to a site remote from the painful area in a stimulus point-specific way and the effect of EA in ankle sprain pain is, at least in part, mediated by spinal α-adrenoceptor mechanisms. As a "from bench to bedside study", we examined the preemptive analgesia of acupuncture in inflammatory pain. EA was applied prior to the induction of inflammation. Pretreatment of EA applied to ST-36 significantly prevented hyperalgesia. However, EA applied to control point was not effective. Furthermore, the effect of EA was blocked by intraperitoneal injection of naloxone. These data suggest that EA could be used as preemptive analgesic treatment on inflammatory pain in human. Complementing these studies are laboratory investigations of clinical use that contribute to a fuller understanding of the acupuncture. [J Physiol Sci. 2008;58 Suppl:S7]
