Physiologische Mechanismen der analgetischen Akupunkturwirkung – ein Update im klinischen Kontext

Abstract

BackgroundPhysiological mechanisms of pain relief achieved by acupuncture are subject to three decades of intensive research. ObjectiveTo give an overview about the current knowledge on mechanism underlying acupuncture induced analgesia MethodsAn extensive literature search based on significant reviews of the last years was performed. Secondary literature was reviewed and Medline searches using respective keywords were carried out. Results were summarized in the following sections: 1Importance of endogenous opioids and descending pain inhibitory circuits2Effects on the autonomous nervous system3Impacts on central pain processing4Segmental inhibition5Local mechanisms ResultsThere is substantial evidence for the release of endorphins as a central anti-nociceptive mechanism of acupuncture. With regard to electroacupuncture (EA) it has been suggested that stimulation frequency impacts on treatment outcome. The decisive role of further neuromodulators of the descending pain inhibitory circuits, primarily serotonin and norepinephrine, is well established. Effects of acupuncture on the autonomous nervous system seem likely, but remain largely unclear. In contrast, the impact of acupuncture on central pain processing is well characterized, as well as the activation of segmental inhibition occurring in the spinal cord. The peripheral release of various neuromodulators is also fairly well described as a potential mechanism contributing to acupuncture analgesia. ConclusionAcupuncture induced analgesia is based on a complex interplay of peripheral, spinal and central mechanisms. A large number of basic science and clinical studies support this notion. However it remains largely unclear how these different mechanisms are interwoven and how their contributions to the analgesic acupuncture effect compare to each other. Future studies need to address the specificity of acupuncture points or point regimens and the impact of different types and intensities of needle stimulation. In addition, it needs to be clarified whether the mechanisms identified through animal studies apply to acupuncture in humans as well.