Purinergic mechanisms mediate acupuncture-induced analgesia

Pain is one of the conditions which verifiably benefits from acupuncture (AP) treatment in clinics. In spite of convincing meta-analyses of randomized, sham controlled clinical investigations or evaluated Cochrane reviews, there is still some disbelief about the efficiency of this therapeutic maneuver (1,2). In fact, it is hard to understand why AP strongly relieves some types of pain (low back pain, neck pain, osteoarthritis), while leaving other types of probably similar etiology only slightly or not at all affected (dental pain, coloscopy and intraoperative pain). Moreover, the strongest evidence for a positive outcome of AP treatment is in the case of postoperative nausea and vomiting, conditions not related to pain. Convincing arguments for the efficiency of AP, especially of electroacupuncture (EAP) in case of various painful conditions, were supplied by experiments on laboratory rodents (3,4). In this Editorial Commentary we will reflect to ideas presented in these overviews. The authors refer to numerous original publications supporting the participation of endogenous opioid peptides in AP-induced analgesia both in animals and human subjects (4). Thereafter they emphasize that in addition to peripheral and central opioids, purinergic signaling also contributes to analgesia.