Background. Experimental studies have demonstrated that intracoronary platelet aggregation and thrombus formation may induce marked vasoconstriction of epicardial arteries with endothelial injury. Methods and Results. To examine the effects of intracoronary thrombus formation on coronary vasomotor tone of human epicardial arteries in vivo, we studied 15 patients who developed intracoronary thro...

BACKGROUND Noradrenergic vascular hyper-responsiveness is a hallmark of essential hypertension. To evaluate whether nitric oxide plays a role in the enhanced vascular response to norepinephrine in hypertension, we examined 32 hypertensives and 28 normotensives who were distributed in 3 experimental series. METHODS AND RESULTS In the first series, we measured the forearm blood flow (FBF) respo...

Yamaguchi O, Kaneshiro T, Saitoh S, Ishibashi T, Maruyama Y, Takeishi Y. Regulation of coronary vascular tone via redox modulation in the 1-adrenergic-angiotensin-endothelin axis of the myocardium. Am J Physiol Heart Circ Physiol 296: H226–H232, 2009. First published November 21, 2008; doi:10.1152/ajpheart.00480.2008.—We hypothesized that 1-adrenoceptor stimulation of cardiac myocytes results i...

Humans encounter hypoxia throughout their lives. This occurs by destiny in utero, through disease, and by desire, in our quest for altitude. Hypoxic pulmonary vasoconstriction (HPV) is a widely conserved, homeostatic, vasomotor response of resistance pulmonary arteries to alveolar hypoxia. HPV mediates ventilation-perfusion matching and, by reducing shunt fraction, optimizes systemic Po(2). HPV...

Vasoconstriction is not recognized as a cause of cerebrovascular disease except in the vasospasm seen following subarachnoid hemorrhage and possibly in migraine. However, we found four patients to have transient, fully reversible vasoconstriction and dilatation prominently involving arteries around the circle of Willis. All four patients were evaluated for severe headaches and fluctuating or re...

Pulmonary vascular resistance normally falls or remains unchanged during exercise. Seven children with pulmonary hypertension were exercised during cardiac catheterisation after operative correction of ventricular septal defect (6) and truncus arteriosus (1). Except for the presence of moderate pulmonary hypertension, resting haemodynamics in these seven children were similar to those of normal...

By cutting gill filaments in anesthetized rainbow trout ( Oncorhynchus mykiss), observing the bleeding through a stereomicroscope, and using blockers of various known endogenous filament artery vasoconstrictors, we have here attempted to characterize hemostatic mechanisms in gills. The immediate hemostatic response to a cut in a gill filament artery was a local vasoconstriction, stopping the he...

The isolated kidney of the recipient rat was perfused at a fixed flow rate with blood from a donor by a cross-circulation technique. The renal vasculature responded to the release of arterial occlusion with vasoconstriction, the magnitude of which was increased with increase in the duration of occlusion. ATP, ADP, AMP, adenosine, noradrenaline and 5-HT injected into the renal artery induced a p...

Vasoconstriction is a normal response to a fall in blood volume, but excessive vasoconstriction caused by pressor drugs, while it raises the arterial pressure, is considered to be undesirable because it decreases the already diminished flow through capillaries (1, 2). Pressor drugs are therefore said to be harmful in shock in which there is a diminished blood volume, although many physicians st...

BACKGROUND Postpartum reversible cerebral vasoconstriction syndrome is one of the rare reversible cerebral vasoconstriction syndromes. The clinical presentation is usually characterized by recurrent headache, focal neurological deficit, and reversible cerebral vasoconstriction seen on cerebral angiography. CASE PRESENTATION We report a case of a 35-year-old Yemeni woman who presented with hea...