Long‐term responses of renal and lumbar sympathetic nerve activity to chronic sino‐aortic denervation in rats

The present study examined a potential role of sympathetic nerve activity in changing mean level and variability of arterial pressure (Pa) observed after sino‐aortic denervation (SAD) in rats. Time courses of changes in renal (RSNA) and lumbar (LSNA) sympathetic nerve activity, Pa, and heart rate (HR) were measured simultaneously and continuously in the same Wistar rat with chronic SAD. Following 3 days control period, rats were subjected to SAD, and then the responses of RSNA, LSNA, Pa, and HR were measured over 15 days thereafter. Mean levels of Pa, HR, RSNA, and LSNA were increased due to SAD and then reached peak values within 2 day after the SAD; subsequently, the mean levels of those parameters decreased gradually and simultaneously, returning to the preoperative levels within 8–10 days after SAD. Standard deviations of Pa and RSNA increased after SAD, while those of LSNA and HR tended to decrease. These data suggest that the changes in mean Pa appear to be closely related to those in mean sympathetic nerve activity, while the changes in variability of Pa could not be simply explained by those in variability of sympathetic nerve activity after SAD in rats. JSPS Grant.