Effects of sinoaortic denervation on blood pressure, pulse interval, sympathetic nerve activity and diaphragmatic electromyogram variability in conscious rats

The effects of sinoaortic denervation on systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse interval (PI), renal sympathetic nerve activity (RSNA) and respiratory activity (RA) were investigated in conscious Wistar rats by wide-band spectral and coherence analysis. Signals were recorded for 90 minutes, six hours after sinoaortic denervation (SAD) in eight such rats, and in eight sham-operated rats. After SAD, the animals showed higher blood pressure (BP) mean and variability, higher heart rate and RSNA, and lower PI variability and respiratory frequency. The rhythmic component centred at 0.4 Hz, seen in RSNA in sham rats was blunted after SAD. The results suggest that PI variability and the RSNA component at 0.4 Hz depend on baroreceptors and may contribute to regulating BP within a physiological range of variability