OBJECTIVE The present study was designed to examine in the human omental artery whether high concentrations of D-glucose inhibit the activity of ATP-sensitive K+ channels in the vascular smooth muscle and whether this inhibitory effect is mediated by the production of superoxide. METHODS AND RESULTS Human omental arteries without endothelium were suspended for isometric force recording. Chang...

BACKGROUND We examined for the first time the vascular effects of purinergic agents that contribute to the regulation of peripheral vascular resistance in human small renal resistance arteries (hRRAs). METHODS AND RESULTS Diadenosine polyphosphates (ApnAs, n = 3-6) and ATP, mounted in a microvessel myograph, caused vasoconstriction in hRRAs (rank order of potency: Ap5A > Ap6A = Ap4A > Ap3A = ...

OBJECTIVE The vasorelaxant effect of 2-arachidonoylglycerol (2-AG) has been well characterised in animals. 2-AG is present in human vascular cells and is up-regulated in cardiovascular pathophysiology. However, the acute vascular actions of 2-AG have not been explored in humans. APPROACH Mesenteric arteries were obtained from patients receiving colorectal surgery and mounted on a myograph. Ar...

Our objective was to test the hypothesis that acute exposure of human skin vasculature to nicotine may have deleterious effects on endothelial function. Vasoconstriction and vasorelaxation in isolated perfused human skin flaps (approximately 8 x 18 cm) derived from dermolipectomy specimens were assessed by studying changes in skin perfusion pressure measured by a pressure transducer, and skin p...

BACKGROUND Dendroaspis natriuretic peptide (DNP) is the newest member of the natriuretic peptide family and is a circulating peptide in humans. The effects of DNP on the human vasculature are unknown. Since other natriuretic peptides are known to cause vasorelaxation, we determined the response to DNP on human blood vessels in vitro. We also investigated the mechanism of DNP mediated vasorelaxa...

Background: Hypertension is considered an independent risk factor for cardiovascular mortality in diabetic patients. The present study was designed to determine the role of gamma amino butyric acid B (GABAB) receptor and L-arginine (L-Arg) in GABA-induced vasorelaxation in normal and streptozotocin-induced diabetic rat vessels. Methods: Diabetes was induced by a single i.p. injection of strepto...

During everyday life, gravity constantly stresses the cardiovascular system in upright humans by diminishing venous return. This decreases cardiac output and induces systemic vasoconstriction to prevent blood pressure from falling. We therefore tested the hypothesis that entering weightlessness leads to a prompt increase in cardiac output and to systemic vasodilatation and that these effects pe...

Vasorelaxation induced by lysophosphatidylcholine (LPC) and platelet activating factor (PAF) was examined in rings isolated from rat aorta and mesenteric artery. LPC caused dose-dependent vasodilatation, which was sensitive to CV-6209, a PAF antagonist, and NG-monomethyl-L-arginine, a nitric oxide synthase inhibitor, but insensitive to indomethacin. PAF (10(-7)M) caused a tachyphylactic effect ...

Matrix metalloproteinase (MMP)-2 has been historically associated with the process of vascular remodeling through the cleavage of extracellular matrix proteins. However, we recently found that MMP-2 also cleaves the endothelium-derived peptide big endothelin-1, ET-1[1-38] and yields the novel vasoconstrictor ET-1[1-32]. We therefore investigated the effects of MMP-2 inhibitors as potential vaso...