... on its relationship with invasive assessment by phenylephrine injection (Phe-slope). In the present study, we therefore compared these methodologies in a series of patients with HF (heart failure) in which both measures together with clinical and haemodynamic data were available. HRT parameters...

...Grzegorz RACZAK; Maria Teresa LA ROVERE; Gian Domenico PINNA; Roberto MAESTRI; Grayna ŚWITECKA The purpose of the present study was to assess the agreement between measurements of baroreflex sensitivity (BRS) obtained by the Valsalva manoeuvre and by the phenylephrine test in patients with previous...

... operated. In rat aorta, there was no significant difference between portal hypertensive and sham-operated animals in the contractile potency of KCl, noradrenaline or phenylephrine. In aortas from Wistar rats, the maximum response to KCl (0.71±0.12 ;g) and noradrenaline (1.00±0.17 ;g) but not phenylephrine...

... (phenylephrine) stimuli, and their mean. 3. Baroreflex sensitivity was significantly lower in the hypertensive group by the pharmacological, sequence and spectral methods (all P < 0.05). 4. There was acceptable agreement between pharmacological baroreflex sensitivity and sequences of the same direction...

... and that of the endothelium in the response to phenylephrine and acetylcholine of isolated aortic rings from chronic bile duct-ligated (29 days) rats and their corresponding controls. Experiments were performed in rings with or without endothelium, in rings pretreated with N -ω-nitro-l-arginine methyl ester (10 −4 mol/l...

... to study contraction after pressure recording. 3. Octreotide treatment significantly reduced portal pressure and plasma glucagon concentrations compared with the vehicle-treated group. Both phenylephrine and vasopressin induced concentration-dependent contractile responses in the aorta and mesenteric...

... this is due to increased sensitivity at α 1 - or α 2 -adrenergic receptors, we compared vascular responses to the α 1 -adrenergic agonist phenylephrine and the α 2 -adrenergic agonist clonidine. 3. We studied 15 insulin-dependent diabetic patients with microalbuminuria, 15 insulin-dependent diabetic patients...

... heart rate responses to perturbations in mean arterial pressure induced with injections of nitroprusside and phenylephrine. The method provides a sigmoidal relationship between changes in heart rate and blood pressure. The upper plateau (maximum tachycardia in response to blood pressure reduction...

... to catecholamines could be due to either a postsynaptic increase in vascular sensitivity or to decreased catecholamine uptake into peripheral sympathetic nerve endings. 2. To differentiate between these possible mechanisms we have measured the responsiveness in vivo to noradrenaline and phenylephrine with local...

...Seiki Harada; Tsutomu Imaizumi; Michiko Momohara; Hiroyuki Masaki; Shin-Ichi Ando; Akira Takeshita 1. The aim of this study was to examine whether arginine vasopressin modulates the vasoconstricting action of phenylephrine in human forearms. 2. In seven healthy subjects, we determined...

... of 27 conscious rabbits was assessed by both the ‘steady-state’ and ‘ramp’ methods in response to injections of phenylephrine (2.5-30 μg/kg). 2. Animals with differing baroreflex sensitivities were then given 4 weeks treatment with 8% NaCl and 1.3% KCl in food (treatment A), or DOCA (25 mg pellet...

... investigated the effect of injecting the vasoactive drug phenylephrine on the mechanical behaviour of the sinus wall. 2. Baroreflex sensitivity was measured in the dogs by the usual method of relating the slowing of the heart to the transient pressure rise induced by the injections of phenylephrine. 3. We have...

... phenylephrine. 2. Oral prazosin (1 mg) lowered erect (but not supine) blood pressure in both groups by a comparable amount: in young and old groups the respective maximal falls in systolic pressure were 19.5 ± 15.7 and 29.3 ± 11.4 mmHg (mean ± sd) and for diastolic pressure the maximal falls were 13 ± 13.3...

... hypertensive subjects and in 14 age-matched control subjects. 2. Baroreceptor sensitivity was tested by evaluating both heart rate response to phenylephrine-induced increase in arterial pressure, and heart rate and blood pressure changes induced by increasing neck-tissue pressure by means of a neck-chamber. 3...

...M. J. Stevens; R. E. Rittinghausen; R. F. W. Moulds 1. The effects of various α-receptor agonists and antagonists on pre- and post-synaptic α-receptors of human isolated digital arteries and metacarpal (or metatarsal) veins have been studied. 2. The relative potency of phenylephrine compared...

... baroreflex sensitivity as measured by various methods (phenylephrine, neck suction etc.). 5. It is concluded that blood pressure variability increases and heart rate variability decreases with age, but that changes in variability are not so obvious in hypertension. Also, differences in variability among...

...R. Vandongen; K. D. Strang; Marianne H. Poesse; W. H. Birkenhager 1. The effect of α-adrenergic stimulation, with phenylephrine, on isoprenaline-provoked renin secretion was studied in the isolated perfused rat kidney. 2. Infusion of phenylephrine increased renal perfusion pressure and prevented...

...%; the phenylephrine-induced rise of systolic brachial artery pressure was reduced by 36%. 3. During labetalol brachial artery pressure was lowered by 29/15 mmHg in the recumbent position, by 41/23 mmHg at rest sitting, and by 53/23 mmHg at maximal exercise; total peripheral resistance was not significantly affected...