This study tested the hypothesis that acute isocapnic hypoxia results in persistent resetting of the baroreflex to higher levels of muscle sympathetic nerve activity (MSNA), which outlasts the hypoxic stimulus. Cardiorespiratory measures were recorded in humans (26 ± 1 yr; n = 14; 3 women) during baseline, exposure to 20 min of isocapnic hypoxia, and for 5 min following termination of hypoxia. ...

Chronic heart failure (CHF) affects approximately 5.7 million people in the United States. Increasing evidence from both clinical and experimental studies indicates that the sensitivity of arterial baroreflex is blunted in the CHF state, which is a predictive risk factor for sudden cardiac death. Normally, the arterial baroreflex regulates blood pressure and heart rate through sensing mechanica...

: Chronic heart failure is a common clinical condition characterized by persistent excessive sympathetic nervous system activation. The derangement of the sympathetic activity has relevant implications for disease progression and patient survival. Aiming to positively impact patient outcome, autonomic nervous system modulatory therapies have been developed and tested in animal and clinical stud...

To assess baroreflex function under closed-loop conditions, a new approach was used to generate large and physiological perturbations in arterial pressure. Blood pressure (BP) and R-R interval were recorded continuously in 20 healthy young (33 +/- 8 yr) and eight elderly subjects (66 +/- 6 yr). Repeated squat-stand maneuvers at the frequencies of 0.05 and 0.1 Hz were performed to produce period...

Salt-sensitive hypertension is known to be associated with dysfunction of the baroreflex control system in the Dahl salt-sensitive (SS) rat. However, neither the physiological mechanisms nor the genomic regions underlying the baroreflex dysfunction seen in this rat model are definitively known. Here, we have adopted a mathematical modeling approach to investigate the physiological and genetic o...

The effects of chronic treatment with 17β-estradiol on baroreflex control of sympathetic activity were examined in conscious unrestrained ovariectomized rats. Baroreflex function was evaluated by logistic sigmoidal analysis of the relationships between changes in mean arterial pressure (MABP) and changes in heart rate (HR) and splanchnic nerve activity (SNA) when MABP was rapidly increased to 1...

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...

Short-term fluctuations in arterial pressures arising from normal physiological function are buffered by a negative feedback system known as the arterial baroreflex. Initiated by altered biomechanical stretch in the vessel wall, the baroreflex coordinates a systemic response that alters heart rate, cardiac contractility and peripheral vessel vasoconstriction. In this work, a coupled 3D-0D formu...

It has been suggested that estrogen modulates baroreflex regulation of autonomic function. The present study evaluated the effects of estrogen on baroreflex regulation of heart rate in response to changes in blood pressure with phenylephrine (PE), ANG II, and sodium nitroprusside (SNP) in a conscious mouse model. Males and ovariectomized females with (OvxE+) and without (OvxE-) estradiol replac...