1. In pentobarbitone-anaesthetized dogs, prazosin (2 x 1-3 micronmol day-1 kg-1; 2 x 0-5 mg day-1 kg-1) administered orally for 3 days reduced resting aortic blood pressure as well as the pressor response to bilateral carotid occlusion. Prazosin neither affected resting heart rate nor the tachycardia induced by intravenous isoprenaline, noradrenaline and electrical stimulation of preganglionic ...

The acute hemodynamic effects of oral prazosin were investigated in 7 patients with chronic refractory heart failure. A single dose of 1 to 3 mg prazosin produced a significant increase in cardiac index (+17.6%, p less than 0.01) associated with substantial decreases in pulmonary arterial diastolic pressure (-31.6%, p less than 0.02), systemic vascular resistance (-29.7%, p less than 0.01), and...

BACKGROUND Exercise-induced dilation of coronary resistance vessels is limited by alpha-adrenergic mechanisms. However, the effect of alpha-adrenergic mechanisms on large coronary arteries during exercise is not known. METHODS AND RESULTS In the present study, sonomicrometry was used to measure circumflex coronary arterial diameter during treadmill exercise before and after alpha 1-adrenergic...

Background. Exercise-induced dilation of coronary resistance vessels is limited by a-adrenergic mechanisms. However, the effect of a-adrenergic mechanisms on large coronary arteries during exercise is not known. Methods and Results. In the present study, sonomicrometry was used to measure circumflex coronary arterial diameter during treadmill exercise before and after al-adrenergic blockade wit...

Intravenous administration of the vasodilator sodium nitroprusside has beneficial haemodynamic effects in subjects with severe aortic regurgitation while acute digitalisation can produce unwanted effects associated with an increase in systemic vascular resistance. This study compares the haemodynamic effects of the vasodilator prazosin and digoxin in eight patients with isolated severe aortic r...

To test the hypothesis that the hypotensive action of urapidil is in part related to a direct action on the brain, the central (intracerebroventricular) and peripheral (intravenous) effects of urapidil were studied and compared with those obtained with clonidine and prazosin. All studies were conducted in conscious, chronically instrumented stroke-prone spontaneously hypertensive rats (SHRSP). ...

We determined the binding affinity of tamsulosin, a selective α(1)-adrenoceptor antagonist, for human α(1)-adrenoceptor subtypes in comparison with those of other α(1)-adrenoceptor antagonists including silodosin, prazosin, 5-methylurapidil, terazosin, alfuzosin, nafopidil, urapidil and BMY7378. The association and dissociation kinetics of [(3)H]tamsulosin for recombinant human α(1)-adrenocepto...

Effect of Prazosin on Dynamic Cerebral Autoregulation During Acute Hypotension in Healthy Human Subjects To the Editor: Cerebral blood flow is excellently autoregulated when mean arterial pressure is between 65 and 140 mm Hg.1 In the study by Ogoh et al,2 although the decrement in mean arterial pressure (MAP) in the 2 groups were similar, the MAP fell below the lower limits of cerebral autoregu...

Although the cerebrovasculature is known to be exquisitely sensitive to CO(2), there is no consensus on whether the sympathetic nervous system plays a role in regulating cerebrovascular responses to changes in arterial CO(2). To address this question, we investigated human cerebrovascular CO(2) reactivity in healthy participants randomly assigned to the α(1)-adrenoreceptor blockade group (9 par...