Aim: The aim of this review is to present the findings of basic research about mechanism of acupuncture-induced analgesia (AA) on the basis of the relevant literature. The transferability of the results into practice and theory of traditional acupuncture are critically discussed.
Method: Extensive literature research was used to identify and summarize relevant studies.
Results: AA has been proven by biochemical, immunohistochemical, molecular biological and neurophysiological investigations. It has been shown that short term AA is mediated by an activation of endogenous antinociceptive systems and descending inhibitory systems. Long term effects cannot be explained sufficiently by experimental results; however, they suggest an involvement of long term inhibitory synaptic modification at spinal cord neurons and clinical and radiological findings indicate limbic system modulation.
Conclusion: Regarding the complexity of endogenous pain-inhibitory systems and the methodological shortcomings many questions remain unanswered. Further research activities are necessary in this field.