抄録
Although there are many clinical case reports, electroacupuncture for cardiovascular diseases is not a sure cure. To increase the efficacy of electroacupuncture, in prior study we demonstrated that electroacupuncture at Zusanli reset the arterial baroreflex neural arc to lower sympathetic nerve activity, which moved the operating point of baroreflex toward lower arterial pressure and sympathetic nerve activity (Am J Physiol Heart Circ Physiol. 2006, 291(1), H318-26). However, the strength of electroacupuncture we used was relatively weak. Therefore, in this study, we have systematically investigated the effects of electroacupuncture on sympathetic nerve activity and arterial pressure from low (<1 Hz) to high (100 Hz) stimulation frequency in anesthetized rabbits (n=8). The sympathetic nerve activity and arterial pressure decreased in response to weak (<5Hz) electroacupuncture. However, during moderate stimulation (5-10 Hz), they first decreased and turned to increased their baseline levels within 1 min. During high stimulation (10-100 Hz), they increased without the initial drops. Computer simulation study based on these results suggests that effects of electroacupuncture on the sympathetic nervous and arterial pressure responses are characterized by low-pass filter with low intensity threshold (gain<0), high-pass filter with moderate intensity threshold (gain>0) and low-pass filter with high intensity threshold (gain>0). These findings may have a merit to develop closed-loop electroacupuncture system. [J Physiol Sci. 2008;58 Suppl:S53]
