Short and long term variability of systolic blood pressure and pulse interval in intact and baroreceptor denervated cats

The effects of the surgical opening of the baroreflex loop on the spectral components of systolic blood pressure (SBP) and pulse interval (PI) variability in 8 unrestrained cats are analyzed. In each cat, the spectral characteristics were estimated from intraarterial blood pressure tracings recorded before and after surgical sino-aortic baroreceptor denervation (SAD). The analysis focused on two different spectral regions. The first region included spectral components having periods ranging from 1.6 to 40 seconds, while the second region (partially overlapping the first one) included components with periods from 10 seconds up to 1.5 hours. The opening of the baroreflex loop caused nonhomogeneous effects on the various components of SBP and PI variability. These findings evidence a differentiated involvement of the baroreceptors in controlling SBP and PI variations characterized by different time constants