[A Systematical Review of Researches on Oxygen Specificity in the Acupoint Area]

Oxygen, an important substance for metabolism, and its related nitric oxide (NO) and carbon dioxide (CO₂) play a key role in regulating physiological activities. The study on the characteristics of oxygen in the acupoint region has been being conducted for nearly 30 years. In the present paper, the authors review recent development of researches on changes of partial oxygen pressure (PO₂), NO, and CO₂ levels in the acupoint regions. Some researches demonstrated that the PO₂, CO₂ and NO contents are relatively higher in some acupoints as Zusanli (ST 36), etc. in comparison with the neighbor tissues or non-acupoints under normal and pathological states in severe infection patients and rats. After acupuncture stimulation, CO₂ and NO contents were increased, while PO₂ content was increased or lowered in some acupoints not in non-acupoints. However, there were also some arguments about the conclusions of acupoint oxygen specificity. In order to verify the results of acupoint oxygen specificity researches, more attentions should be paid to the precise experimental design, repeatable experimental conditions, homogeneity of subjects, human body observation, Deqi effect of acupuncture needle manipulation, etc. in the future studies.