Electroacupuncture changes the relationship between cardiac and renal sympathetic nerve activities in anesthetized cats

Electroacupuncture (EA) is known to affect hemodynamics through modulation of efferent sympathetic nerve activity (SNA), however, possible regional differences in the SNA response to EA remains to be examined. Based on the discordance between arterial blood pressure and heart rate changes during EA, we hypothesized that regional differences would occur among SNAs during EA. To test this hypothesis, we compared changes in cardiac and renal SNAs in response to 1-min EA (10 Hz or 2 Hz) of a hind limb in adult cats anesthetized with pentobarbital sodium. Renal SNA remained decreased for 1 min during EA (P < 0.01 for both 10 Hz and 2 Hz). In contrast, cardiac SNA tented to decrease only in the beginning of EA. It increased during the end of EA (P < 0.05 for 2 Hz) and further increased after the end of EA (P < 0.01 both for 10 Hz and 2 Hz). There was a quasi-linear relationship between renal and cardiac SNAs with a slope of 0.69 (i.e., renal SNA was more suppressed than cardiac SNA) during the last 10 s of EA. The discrepancy between the renal and cardiac SNAs persisted after sinoaortic denervation and vagotomy. In conclusion, EA evokes differential patterns of SNA responses and changes the relationship between cardiac and renal SNAs.