Mechanisms regulating blood pressure in the conscious rat: investigation by Wigner-Ville analysis

Wigner-Ville (WV) analysis was used to investigate rapidly varying spectral characteristics of blood pressure variability in rats following sinoaortic deafferentation (SAD). SAD abolished the 0.5 Hz peak attributed to the baroreflex while increasing low-frequency power by 10-100 times, and a prominent peak appeared at the observed frequency of respiration (1.5-2.0 Hz). In sham-operated rats, small amplitude rapid fluctuations in power at the lower frequencies apparently represent baroreflex activity. SAD removed these rapid fluctuations, and caused a dramatic increase in the amplitude of low frequency power fluctuations. After SAD, the mechanisms mediating low and high frequency oscillations may compensate for the abolished baroreflex by increasing their sensitivity.<>