Search results for "dilation"
showing 10 items of 304 documents
Chronic exercise impairs nitric oxide pathway in rabbit carotid and femoral arteries
2018
KEY POINTS: Some of the beneficial effects of exercise in preventing vascular related diseases are mediated by the enhancement of endothelial function where the role of nitric oxide (NO) is well documented, although the relevance of calcium activated potassium channels is not fully understood. The impact of oxidative stress induced by training on endothelial function remains to be clarified. By evaluating different endothelial vasodilator pathways on two vascular beds in a rabbit model of chronic exercise, we found a decreased NO bioavailability and endothelial nitric oxide synthase expression in both carotid and femoral arteries. Physical training induced carotid endothelial dysfunction as…
Chronic Administration of Quercetin Induces Biomechanical and Pharmacological Remodeling in the Rat Coronary Arteries
2017
Acute dilation brought about by the dietary flavonoid quercetin in coronary arterioles has been described earlier, but no information is available on its chronic effects. Male Wistar rats (body weight about 190 g) were divided to two groups: the quercetin-treated group (n=22) had quercetin supplementation of approximately 30 mg/kg/day, whereas the control group (n=20) had none. After eight weeks of treatment, intramural coronary arterioles with identical passive diameters (178+/-14 microm and 171+/-9 microm) were prepared and their biomechanics and pharmacological reactivities were tested using pressure arteriography ex vivo. The spontaneous tone of quercetin-treated arteries was higher (16…
Vasoactive properties of antihypertensive lactoferrin-derived peptides in resistance vessels: Effects in small mesenteric arteries from SHR rats
2017
Aims: Bovine lactoferrin (LF) hydrolysates and peptides identified thereof have shown antihypertensive effects in rat models, mainly but not exclusively by angiotensin-converting enzyme inhibition. In this study we aimed to assess the vasoactive effects and mechanisms of an ultrafiltered (< 3 kDa) pepsin LF hydrolysate (LFH) and a heptapeptide identified in a LF hydrolysate produced by yeast proteolysis (DPYKLRP) in peripheral resistance arteries from spontaneously hypertensive rats (SHRs). Main methods: We used a myograph system for isometric tension recording in isolated small mesenteric arteries from SHRs. Direct vasoactive effects of LFH (30–100 μg/mL) and DPYKLRP (30–100 μM) were asses…
Aspirin and COX-2 Inhibitor Nimesulide Potentiate Adrenergic Contractions of Human Gastroepiploic Artery
2007
Background The aim of the present study was to evaluate the intervention of COX-1- and COX-2-derived prostaglandins in the responses of human gastroepiploic artery to sympathetic stimulation and norepinephrine. Methods Rings of human gastroepiploic artery were obtained from 45 patients (26 men and 19 women) undergoing gastrectomy. The rings were suspended in organ baths for isometric recording of tension. We studied the responses to electrical field stimulation, norepinephrine, and acetylcholine, in the absence and presence of COX-1 or COX-2 inhibition. Results The COX-1 and COX-2 inhibitor aspirin at high concentrations (10 −6 to 10 −5 mol/L) and the COX-2 inhibitor nimesulide (10 −6 mol/L…
Riociguat versus sildenafil on hypoxic pulmonary vasoconstriction and ventilation/perfusion matching
2017
Introduction Current treatment with vasodilators for pulmonary hypertension associated with respiratory diseases is limited by their inhibitory effect on hypoxic pulmonary vasoconstriction (HPV) and uncoupling effects on ventilation-perfusion (V'/Q'). Hypoxia is also a well-known modulator of the nitric oxide (NO) pathway, and may therefore differentially affect the responses to phosphodiesterase 5 (PDE5) inhibitors and soluble guanylyl cyclase (sGC) stimulators. So far, the effects of the sGC stimulator riociguat on HPV have been poorly characterized. Materials and methods Contraction was recorded in pulmonary arteries (PA) in a wire myograph. Anesthetized rats were catheterized to record …
Vascular effects and safety of dalcetrapib in patients with or at risk of coronary heart disease: the dal-VESSEL randomized clinical trial
2012
Aims High-density lipoprotein cholesterol (HDL-C) is inversely associated with cardiovascular (CV) events and thus an attractive therapeutic target. However, in spite of marked elevations in HDL-C, the first cholesterol transport protein (CETP) inhibitor torcetrapib raised blood pressure (BP), impaired endothelial function, and increased CV mortality and morbidity. Dalcetrapib is a novel molecule acting on CETP with a different chemical structure to torcetrapib. As HDL stimulates nitric oxide (NO), suppresses inflammation, and exerts protective CV effects, we investigated the effects of dalcetrapib on endothelial function, blood pressure, inflammatory markers, and lipids in patients with, o…
Role of endothelial nitric oxide in pulmonary and systemic arteries during hypoxia
2014
Abstract Our aim was to investigate the role played by endothelial nitric oxide (NO) during acute vascular response to hypoxia, as a modulator of both vascular tone (through guanylate cyclase (sGC) activation) and mitochondrial O2 consumption (through competitive inhibition of cytochrome-c-oxydase (CcO)). Organ bath experiments were performed and O2 consumption (Clark electrode) was determined in isolated aorta, mesenteric and pulmonary arteries of rats and eNOS-knockout mice. All pre-contracted vessels exhibited a triphasic hypoxic response consisting of an initial transient contraction (not observed in vessels from eNOS-knockout mice) followed by relaxation and subsequent sustained contra…
Midostaurin upregulates eNOS gene expression and preserves eNOS function in the microcirculation of the mouse
2005
Nitric oxide (NO) derived from endothelial NO synthase (eNOS) is a powerful vasodilator and possesses vasoprotective effects. Therefore, augmentation of eNOS expression and -activity by pharmacological means could provide protection against cardiovascular disease. However, this concept has been questioned recently, because in several disease models, eNOS upregulation was associated with a dysfunctional enzyme (referred to as eNOS uncoupling). In contrast, the present study demonstrates that an eNOS gene expression-enhancing compound with additional protein kinase C (PKC) inhibitory properties can upregulate eNOS while preserving its enzymatic function. Apolipoprotein E-knockout mice were tr…
Role of the Endothelium in the Relaxation Induced by Propofol and Thiopental in Isolated Arteries from Man
1997
Abstract Induction of anaesthesia with intravenous propofol and thiopental is often accompanied by hypotension. This study evaluates whether propofol and thiopental induce relaxation of isolated arteries from man and whether this effect is modulated by the endothelium. Mesenteric artery rings (with and without endothelium) from 12 patients were placed in organ baths and precontracted with phenylephrine before addition of propofol (10−3 M) or thiopental (10−3 M). Relaxation induced by propofol and thiopental was evaluated for rings with intact endothelium in the presence of the nitric oxide synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME; 10−4 M) or the cyclooxygenase inhibitor i…
Endothelium- and nitric oxide-dependent vasorelaxing activities of gamma-butyrobetaine esters: possible link to the antiischemic activities of mildro…
2004
Mildronate [3-(2,2,2-trimethylhydrazine) propionate (THP)] is an antiischemic drug acting mainly via inhibition of fatty acid beta-oxidation. Some effects of the drug cannot be explained by the latter mechanism. We tested the eventual nitric oxide (NO) dependence of the mildronate action. Mildronate, gamma-butyrobetaine (GBB) and GBB methyl ester induced transient increases in nitric oxide (NO) concentrations in rat blood and myocardium. In vitro, these compounds neither modified the activities of purified neuronal and endothelial recombinant nitric oxide synthases (NOSs) nor were able to interact with their active site. GBB induced vasodilatation at high concentrations only (EC50 = 5 x 10(…