Cardiovascular beneficial effects of electroacupuncture at Neiguan (PC-6) acupoint in anesthetized open-chest dog

Neiguan (PC-6) is a traditional acupoint in the bilateral forearms, overlyi ng the median nerve trunk. Neiguan electroacupuncture (EA) has been believe d to affect cardiovascular function and used in traditional Chinese medicin e to improve or treat a wide range of health conditions and diseases, inclu ding angina pectoris, myocardial infarction, hypertension, and hypotension. However, few physiological studies have assessed the beneficial effects of Neiguan EA on the cardiovascular function. In the present study, we invest igated its effects on the cardiovascular function in normal open-chest dogs under pentobarbital and fentanyl anesthesia. We also obtained left ventric ular (LV) pressure-volume (P-V) data with a micromanometer catheter and a v olumetric conductance catheter. Mean arterial pressure, end-diastolic volum e, heart rate, stroke volume, cardiac output, and end-systolic pressure gra dually decreased by 5 to 10% over 1.5 h without Neiguan EA. Neiguan EA at 4 0 Hz, however, increased these cardiovascular variables by 10 to 15%, espec ially end-systolic elastance (Ees) by 40% (p <0.05) over 15 to 60 min. Afte r Neiguan EA was stopped at 1 h, these facilitated cardiovascular variables decreased below the pre-EA level. This beneficial effect of electroacupunc ture may contribute to the effectiveness of the acupuncture in Chinese medi cine.