Objective assessment of the sympatholytic action of the Nei-Kuan acupoint.

From animal experiments and clinical trials, we can think that acupuncture of Nei-Kuan (EH-6) is effective in the control of some vegetative functions. We have tried to determine the real reach of these assumptions by means of simple quantitative measurement methods, such as detection of cardiac frequency and systolic and diastolic blood pressure, and the sympathetic electrical response. The experiments were performed on 29 healthy volunteers. Basal values of these parameters were recorded, and also after orthodox Nei-Kuan acupuncture, non-acupunctural point puncture, supine lying by 15 min, Chü-Tze (EH-3) acupuncture and bipolar electrical stimulus of the median nerve at the Nei-Kuan level in the wrist. Such conditions were designed to evaluate non-specific puncture, repose and direct median nerve stimulation influences in the effects of Nei-Kuan acupuncture. We conclude that Nei-Kuan acupuncture strongly inhibits sympathetic tone, with reduction of cardiac frequency, systolic blood pressure and an important reduction of the amplitude of the sympathetic electrical response; the latency of the electrical response was also prolonged. Some weak effects on blood pressure and cardiac frequency were observed also, as non-specific effects of puncture and median nerve stimulation. From previous anatomical data, we hypothesize that the level of such actions is suprametameric, with strong implication of the diencephalon and cerebral cortex.