Abstract
The mechanism by which acupuncture stimulation increases blood flow in the remote area has been attributed
to the involvement of the supraspinal reflex. However, in our preliminary experiments, we observed phenomena
that could not be explained solely by the involvement of supraspinal reflexes. Since nitric oxide is involved
in vasodilation and since nitric oxide diffuses into the blood and binds to hemoglobin, we hypothesized that nitric
oxide generated by acupuncture stimulation is carried by the blood and causes vasodilation in remote areas. In this study, we conducted experiments to verify the presence of nitric oxide and the resulting vasodilation phenomenon in humans by measuring transcutaneous oxygen saturation (SpO2) and heart rate (HR) using a fingertip volumetric pulse wave meter, and by measuring vascular diameter using a blood flow scope. As a result, the closer the acupuncture point was to the measurement site, the shorter the time until the vasodilation caused by nitric oxide occurred at the measurement site. This suggests that nitric oxide generated by acupuncture diffuses into the blood, binds to hemoglobin, and is transported to peripheral blood vessels, contributing to peripheral vasodilation in remote areas.
