Wavelet-based analysis of low-frequency fluctuations of blood pressure and sympathetic nerve activity in rats.
Biorthogonal wavelets were employed to quantify the relationship of fluctuations between blood pressure (BP) and sympathetic nerve activity (SNA). We forced the SNA to fluctuate by electrical stimulation the medulla in anesthetized, paralyzed, vagotomized, cardiac sympathetic-blocked, baroreceptor-denervated, and angiotensin II-converting enzyme-inhibited rats. Although spectral analysis showed a close coupling between fluctuations of BP and SNA at the stimulating frequencies, only the fluctuations of SNA in frequencies of 0.25 to approximately 0.4 Hz were proportional to BP fluctuations over the course of time. The results suggest that fluctuations transmitted from SNA to BP were uniform without shifting due to the nature of vasculature or the lagging of sympathetic action in frequencies of 0.25 to approximately 0.4 Hz, and support the possibility of using low-frequency variabilities of BP to quantitatively estimate fluctuations of SNA at time domain.
Tsai
Meng-Li
ML
Department of Biomachtronic Engineering, National Ilan University, No. 1 Shen Lung Rd., Sect. 1, Ilan 260, Taiwan. mltsai@niu.edu.tw
Shann
Wei-Chang
WC
Luo
Wen-Ren
WR
Yen
Chen-Tung
CT
D000200:Action Potentials / Q000502:physiology*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D001808:Blood Vessels / Q000294:innervation* / Q000502:physiology*; D004558:Electric Stimulation; D005583:Fourier Analysis; D008297:Male; D010507:Periodicity; D051381:Rats; D017208:Rats, Wistar; D012815:Signal Processing, Computer-Assisted; D017779:Sympathetic Fibers, Postganglionic / Q000502:physiology*; D014628:Vagotomy; D014666:Vasomotor System / Q000502:physiology*
D000806:Angiotensin-Converting Enzyme Inhibitors