Cardiac baroreflex function may be assessed from spontaneous fluctuation of systolic arterial pressure (SAP) and R-R interval. In previous studies, time-domain sequence and cross-spectral analysis had been applied to present the baroreflex response of cardiac system. Detrended fluctuation analysis (DFA) is also a promising algorithm to evaluate the fluctuations under various timescales. Thus, w...

Age-related impairments in baroreflex sensitivity in Sprague-Dawley rats are associated with low solitary tract nucleus content of angiotensin-(1-7). However, transgenic rats with low-brain angiotensinogen resulting from glial overexpression of an antisense oligonucleotide to angiotensinogen (ASrAOGEN) are spared age-related declines in cardiovascular function characteristic of Sprague-Dawley r...

ACE inhibitors are extensively used in the treatment of hypertension mainly because of their efficiency in reducing blood pressure levels and decreasing vascular and cardiac hypertrophy. In addition, ACE inhibitors improve baroreceptor reflex control. Chronic inhibition of ACE produces (in addition to decreased angiotensin II levels) a severe increase in angiotensin-(1-7) [Ang-(1-7)] levels in ...

Baroreflex has several branches: reflex control of the peripheral resistance, of the tone of capacitance vessels, of the heart rate and contractility. Heart rate response to blood pressure variations is studied most intensively. Heart rate changes caused by stimulation of baroreceptors are usually quantified as the index of baroreflex sensitivity (BRS), which corresponds to a prolongation of th...

BACKGROUND Our goal was to test sympathetic and cardiovagal baroreflex sensitivity and the transduction of sympathetic traffic into vascular resistance during the early follicular (EF) and midluteal (ML) phases of the menstrual cycle. METHODS AND RESULTS Sympathetic baroreflex sensitivity was assessed by lowering and raising blood pressure with intravenous bolus doses of sodium nitroprusside ...

Spectral and cross-spectral analysis of R-R interval and systolic arterial pressure (SAP) spontaneous fluctuations have been proposed for noninvasive evaluation of baroreflex sensitivity (BRS). However, results are not in good agreement with clinical measurements. In this study, a bivariate parametric autoregressive model with exogenous input (ARXAR model), able to divide the R-R variability in...

Interactions between mechanisms governing ventilation and blood pressure (BP) are not well understood. We studied in 11 resting normal subjects the effects of sustained isocapnic hyperventilation on arterial baroreceptor sensitivity, determined as the alpha index between oscillations in systolic BP (SBP) generated by respiration and oscillations present in R-R intervals (RR) and in peripheral s...

Maintenance of adequate cerebral perfusion during normal physiological challenges requires integration between cerebral blood flow (CBF) and systemic blood pressure control mechanisms. Previous studies have shown that cardiac baroreflex sensitivity (BRS) is inversely related to some measures of cerebral autoregulation. However, interactions between the sympathetic arterial baroreflex and cerebr...

This study tested the hypothesis that the discharge patterns of action potentials (APs) within bursts of postganglionic muscle sympathetic nerve activity (MSNA) are subject to arterial baroreflex control but in a manner that varies inversely with AP size. MSNA data were collected over 5 min of supine rest in 15 young and healthy individuals (8 males; 24 ± 4 yr of age; means ± SD). The barorefle...

BACKGROUND orthostatic hypotension in elderly people is often attributed to diminished afferent baroreflex sensitivity, but this has not been demonstrated. We examined the hypothesis that postural change in blood pressure is related to baroreflex sensitivity, independent of the confounding effect of baseline blood pressure. METHODS we studied 25 active, untreated elderly subjects free of post...