Electroacupuncture analgesia in rat ankle sprain pain model: neural mechanisms. 
Acupuncture, an alternative medical therapy with a long history, is appealing because it can activate endogenous analgesic mechanisms by minimally invasive means.  The mechanisms of acupuncture, however, are not well understood yet.  The following sentence was removed from our original manuscript.  One of the major problems impeding understanding of the acupuncture mechanism is lack of experimental models that mimic various forms of persistent pain that respond to acupuncture in humans.  In this review, we summarize and discuss previous and recent findings regarding electroacupuncture-induced analgesia in an ankle sprain pain model and the potential underlying mechanisms of acupuncture.  A novel model of ankle sprain pain is introduced recently and the mechanism of electroacupuncture-induced analgesia in this model has been explored.  The following sentence was removed from our original manuscript.  This model provides a reproducible and quantifiable index of persistent pain at the ankle joint in rats.  Acupuncture at a remote site produces long-lasting and powerful analgesia.  The consistent analgesic effect of acupuncture in this model has allowed us to pursue the underlying neural mechanisms.  These studies provide insight into the mechanisms of acupuncture analgesia in one particular form of persistent pain, and hopefully will allow us to expand our knowledge to other painful conditions.