EFFECTS OF SINOAORTIC DENERVATION ON SPECTRAL CHARACTERISTICS OF BLOOD-PRESSURE AND PULSE INTERVAL VARIABILITY - A WIDE-BAND APPROACH

Sino-aortic denervation (SAD) is employed in cats to evaluate the baro reflex influence on blood pressure (BP) and pulse interval (PI) spectr al components from 0 . 00008 to 0 . 9 Hz as assessed by FFT wide-band spectra and their 1/f modelling; and the linear coupling between BP an d PI and between systolic and diastolic BP as assessed by coherence an alysis. Specific procedures have been developed to obtain an effective smoothing of spectra and coherence functions. SAD induced an increase in BP powers from 0 . 03 to 0 . 0006 Hz and a power reduction of most of the remaining BP components; a reduction of PI powers at all frequ encies; marked deviations of BP spectra from the 1/f trend; a reductio n of the coherence between BP and PI from 0 . 12 to 0 . 5 Hz and a coh erence enhancement at lower frequencies. These findings indicate that the arterial baroreflex modulates both fast and slow spectral componen ts of BP and PI; homogeneously enhances PI fluctuations at all frequen cies; produces differentiated effects on BP fluctuations along the fre quency axis; and at low frequencies exerts the buffering action on BP through strategies which reduce the BP-PI linear link.