David R. Brown, Laura V. Brown, Abhijit Patwardham, and David C. Randall
Am J Physiol. 1994 Nov;267(5 Pt 2):R1378-84
This study looked at the interactions of sympathetic nerve activity (SNA), blood pressure (BP), and heart rate (HR) at the 0.4Hz frequency. As where the studies in our lab are looking at the changes of signal coherence of active and sedentary conditions is study look at the coherence in rats while they rested in a cloth sock, roamed freely in there home cage, and after anesthesia. The data was obtained in a similar method that our lab uses. Electrodes were attached to the renal sympathetic nerve to measure SNA, while catheters were placed in the left jugular and aorta to administer drugs. All the data for each rat was collected over a 9.56 min period. The data showed in conscious rats that SNA frequency peaked at 0.4Hz while the BP and HR were at lower frequency's. Although they did note that the BP did display a some higher 0.4Hz frequency not seen in HR. The coherence of the SNA - BP was at its highest at the 0.4Hz and declined as the frequency got lower. Anesthesia did not change the coherence of SNA - BP. This study shows that SNA and BP are coupled at the 0.4Hz frequency and suggest that maybe BP reflects SNA. I agree with these results because SNA results from output of rostral ventral lateral medulla (RVLM) unit neurons which are influenced by BP.
-Zachery
This study looked at the interactions of sympathetic nerve activity (SNA), blood pressure (BP), and heart rate (HR) at the 0.4Hz frequency. As where the studies in our lab are looking at the changes of signal coherence of active and sedentary conditions is study look at the coherence in rats while they rested in a cloth sock, roamed freely in there home cage, and after anesthesia. The data was obtained in a similar method that our lab uses. Electrodes were attached to the renal sympathetic nerve to measure SNA, while catheters were placed in the left jugular and aorta to administer drugs. All the data for each rat was collected over a 9.56 min period. The data showed in conscious rats that SNA frequency peaked at 0.4Hz while the BP and HR were at lower frequency's. Although they did note that the BP did display a some higher 0.4Hz frequency not seen in HR. The coherence of the SNA - BP was at its highest at the 0.4Hz and declined as the frequency got lower. Anesthesia did not change the coherence of SNA - BP. This study shows that SNA and BP are coupled at the 0.4Hz frequency and suggest that maybe BP reflects SNA. I agree with these results because SNA results from output of rostral ventral lateral medulla (RVLM) unit neurons which are influenced by BP.
-Zachery
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