1. Sensitivity of the sino-aortic baroreflex was investigated before and after acute (23 patients) and chronic (23 patients) beta-adrenoreceptor antagonism in patients with essential hypertension. 2. Sensitivity was inversely related to age (r = -0.60) and systolic blood pressure (r = -0.46); a positive relationship was noted between sensitivity and initial pulse intervals (r = 0.40). 3. Sensit...

BACKGROUND Baroreflex allows to reduce sudden rises or falls of arterial pressure through parallel RR interval fluctuations induced by autonomic nervous system. During spontaneous breathing, the application of positive end-expiratory pressure (PEEP) may affect the autonomic nervous system, as suggested by changes in baroreflex efficiency and RR variability. During mechanical ventilation, some p...

It has been known for many years that baroreflex sensitivity is lowered in hypertensive patients. There are several known factors implicating this association, e.g. high blood pressure leads to remodeling of the carotid arterial wall, to its stiffness and to a diminished activation of baroreceptors; leptin released from a fatty tissue activates the sympathetic nervous system etc. On the other h...

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...

It is well known that cardiac sympathetic afferent reflexes contribute to increases in sympathetic outflow and that sympathetic activity can antagonize arterial baroreflex function. In this study, we tested the hypothesis that in normal rats, chemical and electrical stimulation of cardiac sympathetic afferents results in a decrease in the arterial baroreflex function by increasing sympathetic n...

The prevalence of cardiovascular diseases including hypertension increases dramatically in women after menopause, however the mechanisms involved remain incompletely understood. Oxytocinergic (OTergic) neurons are largely present within the paraventricular nucleus of the hypothalamus (PVN). Several studies have shown that OTergic drive from PVN to brainstem increases baroreflex sensitivity and ...

Baroreflex activity was assessed in 10 fetal lambs at 85-145 days of gestation. ECG leads sewn to the fetal chest wall, vinyl catheters in brachial artery and femoral vein, and a balloon catheter in the descending aorta were exteriorized through the ewe's flank. After at least 36 hours, the reflex bradycardia, in response to increased blood pressure by balloon inflation, was measured. Barorefle...

Baroreceptor sensitivity, reflected by the slope of the linear regression of the electrocardiographic R-R interval on the rise of systolic blood pressure after injection of phenylephrine, was significantly lower in 27 patients with chronic obstructive pulmonary disease (4.67 +/- 2.67) than in 10 normal subjects (12.07 +/- 3.3) of comparable age (p less than 0.001). In 20 patients in whom right ...