Masuki, Shizue, Frank A. Dinenno, Michael J. Joyner, and John H. Eisenach. Selective 2-adrenergic properties of dexmedetomidine over clonidine in the human forearm. J Appl Physiol 99: 587–592, 2005. First published March 31, 2005; doi:10.1152/japplphysiol.00147.2005.— We tested the hypothesis that dexmedetomidine (Dex) has greater 2vs. 1 selectivity than clonidine and causes more 2-selective va...

Acetylcholine (ACh) elicits vasodilation by releasing a number of endothelium-derived relaxing factors (EDRFs). We used the isolated perfused hydronephrotic rat kidney to examine the characteristics of ACh-induced vasodilation of renal afferent arterioles during different types of underlying vasoconstriction. Basal arteriolar tone was increased by either elevating perfusion pressure to 180 mm H...

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...

We used the insulin-perfused human forearm model to assess the effects of vasoconstriction induced with norepinephrine on the extraction of glucose in the forearm in two groups of healthy young volunteers. The norepinephrine findings were compared with a previously studied group in which vasoconstriction has been caused by reflex activation of the sympathetic nervous system. The aim of the stud...

Numerous observational studies have reported an association between serum urate and elevated blood pressure in adult populations (1). These observations, together with experimental vivo studies, generated substantial interest the role of hyperuricaemia as a mediator pressure, various postulated mechanisms, including activation renin-angiotensin system, oxidative stress, reduced endothelial nitr...

The neuronal isoform of nitric oxide synthase (nNOS) is highly expressed in mammalian skeletal muscle, but its functional role has not been defined. NO has been implicated in the local metabolic regulation of blood flow in contracting skeletal muscle in part by antagonizing sympathetic vasoconstriction. We therefore hypothesized that nNOS in skeletal muscle is the source of the NO mediating the...

The stainless steel cannula inserting method was used to examine the effects of methysergide on 5-hydroxytryptamine (5-HT)- and norepinephrine-induced vasoconstriction in the isolated internal carotid artery of the dog. 5-HT, at a dose of 0.3 microgram, induced a marked increase in perfusion pressure, usually over 100 mm Hg. On the other hand, norepinephrine produced a relatively small increase...

Since indomethacin may be effective in the treatment of orthostatic hypotension, the ability of this drug to increase reflex vasoconstriction was studied in six patients with orthostatic hypotension and in five normal subjects. Reflex forearm vasoconstriction during lower body negative pressure at 20-40 mm Hg was measured before and after indomethacin 50 mg by mouth. In patients with orthostati...

Mauban, Joseph R. H., Carmelle V. Remillard, and Jason X.-J. Yuan. Hypoxic pulmonary vasoconstriction: role of ion channels. J Appl Physiol 98: 415–420, 2005. doi:10.1152/japplphysiol.00732.2004.—Acute hypoxia induces pulmonary vasoconstriction and chronic hypoxia causes structural changes of the pulmonary vasculature including arterial medial hypertrophy. Electroand pharmacomechanical mechanis...

In a number of isolated blood vessel types, hypoxia causes an acute contraction that is dependent on the presence of nitric oxide and activation of soluble guanylyl cyclase. It is more pronounced when the preparations are constricted and is therefore termed hypoxic augmentation of vasoconstriction. This hypoxic response is accompanied by increases in the intracellular level of inosine 5'-tripho...