Search Results
Results 551 - 600 of 1225
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Megson I L - - 2000
Photorelaxation of vascular smooth muscle (VSM) is caused by the release of nitric oxide (NO) from a finite molecular store that can be depleted by irradiating pre-contracted arteries with visible light. The ability of an 'exhausted' vessel to respond to a further period of illumination is lost temporarily but then ...
Kondo U - - 2000
BACKGROUND: The objective was to investigate the effects of propofol anesthesia on the pulmonary vascular response to endothelium-dependent and -independent vasodilators, compared with the responses measured in the conscious state. METHODS: Twenty-six conditioned, male, mongrel dogs were instrumented long-term to measure the left pulmonary vascular pressure-flow relation. Pressure-flow plots were ...
Stowe F - - 2000
Increased vascular smooth muscle cyclic guanine monophosphate (cGMP) results in vascular relaxation. The vascular effects of stimulating cGMP production with 10(-8)-10(-4) M nitroprusside (NP) and inhibiting cGMP hydrolysis with 10(-8)-10(-4) M zaprinast (ZAP), a selective type V inhibitor of cGMP phosphodiesterase (PDE), were assessed in isolated guinea pig hearts and ...
Muscará M N - - 2000
Nonsteroidal anti-inflammatory drugs have been reported to exacerbate hypertension. In this study, we tested the hypothesis that a nitric oxide-releasing derivative of naproxen would ameliorate hypertension in the rat. Hypertension was induced by partially occluding one renal artery (the "2K,1C" model), and 2 wk later the rats started receiving naproxen, ...
Wallace J L - - 2000
Nitric oxide (NO) is now recognized as an important modulator of an enormous number of physiological processes, ranging from blood pressure regulation to neuronal transmission to penile erectile function. In the gastrointestinal tract, NO also participates in many physiological and pathophysiological processes. In this review, we summarize the contribution made ...
Paredi P - - 2000
Ethane is a product of lipid peroxidation and can be measured in the exhaled air as an index of oxidative stress. Oxidant/antioxidant imbalance is important in the pathogenesis of chronic obstructive pulmonary disease (COPD). Therefore, we measured exhaled ethane in 22 patients with COPD (mean age +/- SEM, 59 +/- ...
Thompson L P - - 2000
BACKGROUND: Estrogen is cardioprotective of the coronary circulation by mechanisms incompletely understood. This study determined the effect of chronic 17beta-estradiol replacement on dilator responses to acetylcholine and sodium nitroprusside of the isolated coronary microcirculation. METHODS AND RESULTS: Adult female guinea pigs were ovariectomized, and a 21-day-release pellet containing 0.0, 0.1, ...
Horimoto H - - 2000
BACKGROUND: The role of nitric oxide (NO), K(+)(ATP) channels, and cyclic GMP (cGMP) in preconditioning is unknown. MATERIAL AND METHODS: Isolated rabbit hearts were pretreated with the NO precursor L-arginine (L-Arg), both alone and after infusion of the NO synthetase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME). Guanylate cyclase inhibitor methylene blue ...
Sakai H - - 2000
The influence of infusion of a nitric oxide (NO) synthase inhibitor, N(omega)-nitro-l-arginine methyl ester (l-NAME), on resistance arteries (diameter, 150 +/- 8 microm) and its relationship with hypertension were examined in conscious hamsters fitted with a dorsal skinfold window. After infusing l-NAME (10 and 30 mg/kg), hamsters showed immediate hypertension ...
Kublickiene K R - - 2000
OBJECTIVE: We sought to compare flow-mediated dilatation and myogenic and norepinephrine-induced tone in myometrial resistance arteries from women with preeclampsia and healthy pregnant women and to evaluate the role that nitric oxide may play in these responses. STUDY DESIGN: Arteries (approximately 200 microm, at 50 mm Hg) were dissected from ...
Takeda Y - - 2000
OBJECTIVE: Cyclosporine (CysA), a potent immunosuppressant, is associated with hypertension and nephrotoxicity. Neutral endopeptidase (NEP) degrades vasoactive peptides, including the natriuretic peptides and endothelin-1 (ET-1). We conducted the present study to determine whether or not the NEP inhibitor, ecadotril, prevents cyclosporine-induced hypertension and to clarify the mechanisms responsible for the ...
Ben Driss A - - 2000
BACKGROUND: We hypothesized that, in compensated heart failure (HF), hemodynamic perturbations and their consequences exist in pulmonary artery (PA) despite the absence of any perturbation in thoracic aorta (TA). METHODS AND RESULTS: The left coronary artery was ligated in 20 male Wistar rats with compensated HF. Four months after ligation, ...
Day R W - - 2000
BACKGROUND: Inhaled nitric oxide selectively decreases pulmonary vascular resistance. This study was performed to determine whether inhaled nitric oxide decreases the incidence of pulmonary hypertensive crises after corrective procedures for congenital heart disease. METHODS: Patients with a systolic pulmonary arterial pressure of 50% or more of the systolic systemic arterial ...
Vreman H J - - 2000
Metalloporphyrins (MPs) have been found to affect the production of carbon monoxide (CO) and nitric oxide (NO). Unlike that for CO, little is known about the mechanism of action of MPs on the NO system. We determined the in vitro ability of ferrous protoporphyrin (heme, FePP), zinc protoporphyrin (ZnPP), and ...
Intengan H D HD MRC Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, Montreal, Quebec, - - 2000
The antihypertensive agent omapatrilat represents a novel approach to antihypertensive therapy, namely vasopeptidase inhibition. Omapatrilat (BMS-186716) concomitantly inhibits neutral endopeptidase and angiotensin-converting enzyme, leading to protection from degradation of natriuretic and other hypotensive peptides in addition to interruption of the renin-angiotensin system. Although the potency of omapatrilat on reduction of ...
Rehse K - - 2000
Eleven azide oximes were prepared and tested for their antiplatelet (in vitro), antithrombotic, and blood pressure lowering activities. Nine of them inhibited the aggregation of blood platelets (Born test, inducer collagen) with IC50 values between 10 and 50 microM. The most active compounds i.e. azido-4-nitrophenylbenzaldoxime (2h) had an IC50 = ...
Matsuo T - - 2000
BACKGROUND/AIMS: Nitric oxide donors reduce intraocular pressure. Human trabecular cells in culture were examined for their nitric oxide production in response to hydraulic pressure. METHODS: Human trabecular cells were cultured from trabeculum tissue fragments excised during trabeculectomy and exposed to hydraulic pressure change in a culture flask connected to a ...
Pedro-Botet J - - 2000
Several lines of evidence suggest that patients with essential hypertension have impaired endothelial nitric oxide activity and increased superoxide anion production. However, the mechanisms underlying these abnormalities remain unknown. We measured enzymatic superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities in erythrocytes and whole blood, respectively, in 30 newly-diagnosed, normolipidaemic ...
Kadekaro M - - 2000
1. Nitric oxide (NO) tonically inhibits the basal release of vasopressin and oxytocin into plasma. 2. Nitric oxide inhibition on vasopressin secretion is removed, while that on oxytocin is enhanced, during water deprivation, hypovolaemia, moderate osmotic stimulation and angiotensin (Ang)II. This results in a preferential release of vasopressin over oxytocin ...
Harrison R W - - 2000
OBJECTIVE: The nitric oxide synthase inhibitor L-N(G)-methylarginine hydrochloride (L-NMMA HC1 546C88) causes reductions in cardiac output (CO), a potential limitation to clinical application. This drop in CO exceeds that from phenylephrine at matched systemic arterial pressure. We tested the hypothesis that the greater fall in CO attributable to L-NMMA primarily ...
Nakago-Matsuo C - - 2000
To understand orthodontic tooth movement and determine optimal orthodontic force from a biological viewpoint, nitric oxide production in cultured human periodontal ligament fibroblasts was measured at varying levels of hydraulic pressure. The fibroblasts in a culture flask were exposed to the controlled change in hydraulic pressure, and intracellular nitric oxide ...
Hsich E - - 2000
BACKGROUND: Evidence suggests that the vessel wall contains an oxidase similar, if not identical, to phagocytic NADPH oxidase. We tested the contribution of this specific oxidase to the progression of atherosclerosis and the regulation of blood pressure. METHODS AND RESULTS: An examination of aortic rings from wild-type mice and mice ...
Rajek A - - 2000
Heart transplantation in patients with increased pulmonary vascular resistance is often associated with postbypass right heart failure. We therefore compared the abilities of prostaglandin E(1) (PGE(1)) and inhaled nitric oxide to reduce pulmonary vascular resistance during heart transplantation. Patients undergoing orthotopic heart transplantation for congestive heart failure were randomly assigned ...
Pedrinelli R - - 2000
The impact of hypertension on microvascular permeability and nitric oxide-mediated endothelial vasomotion in humans has been studied by measuring either the transcapillary albumin escape rate (TERalb, a measure of permeability through systemic capillary endothelium where most of the albumin permeation takes place) and forearm vasodilatation to locally infused acetylcholine (used ...
Lambert E - - 2000
The demonstration of the effectiveness of endothelin antagonists and nitric oxide donors in managing vasospasm following subarachnoid hemorrhage is encouraging. Whether such drugs can modify the sympathoexcitation that accompanies this condition remains unknown and was the basis for the present report. Subarachnoid hemorrhage was induced in conscious rats by injecting ...
Bocchi E A - - 2000
BACKGROUND: Stimulated endothelium-derived relaxing factor-mediated vasodilation and conduit artery distensibility are impaired in congestive heart failure (CHF). L-arginine could have a potentially beneficial role in CHF, acting through the nitric oxide (NO)-L-arginine pathway or by growth hormone increment. HYPOTHESIS: This study was undertaken to investigate the effects of L-arginine on ...
Jiang J K - - 2000
PURPOSE: A somatoanal reflex had been demonstrated in our previous work. Because nitric oxide plays an important role in mediating relaxation of the internal anal sphincter, our purpose was to examine whether and how local somatothermal stimulation inhibits the function of the internal anal sphincter by stimulating nitric oxide release ...
Mitchell J A - - 2000
Excessive nitric oxide (NO) production in septic shock is thought to contribute to the associated profound hypotension. Here we show that despite induction of NO synthase (NOS) in the hearts of endotoxin-treated rats, coronary vascular responses to the contractile peptide endothelin-1, were not modified. This was not due to any ...
Crippa G E - - 2000
The injection of acetylcholine (ACh) into the cingulate region of the medial prefrontal cortex (MPFC) causes a marked fall in arterial blood pressure which is not accompanied by changes in heart rate. The purpose of the present study was to investigate the hemodynamic basis for this stimulus-induced hypotension in Sprague-Dawley ...
Endo A - - 2000
BACKGROUND: The purpose of the present paper was to evaluate the physiologic significance of nitric oxide (NO) and endothelin (ET)-1 in circulatory adaptation in the neonate. METHODS: The serum levels of NO metabolites (NOx; the sum of nitrites and nitrates) and the plasma level of ET-1 were determined in 14 ...
Duarte J - - 2000
The present article describes the effects of visnagin on systolic blood pressure and heart rate in the anaesthetized rat. Intravenous administration of visnagin (0.3-5 mg kg-1) produced dose-related decreases in blood pressure with no significative changes in heart rate. Under nitric oxide synthase inhibition (L-NAME, 50 mg kg-1) the hypotensive ...
da Cunha V - - 2000
In the present study we investigated the role of cyclooxygenase (COX)-dependent vasoconstrictors in the hypertension and altered vascular reactivity following prolonged nitric oxide (NO) synthase inhibition. Male Wistar rats (250-270 g) were divided into four groups and treated for 7 days with Placebo (control), L-NAME (48 mg/kg/day), indomethacin (4 mg/kg/day) ...
Fernández N - - 2000
The present study examined the role of nitric oxide in coronary vascular tone and in the coronary vasodilatation in response to beta-adrenoceptor stimulation and adenosine. In anesthetized goats, the effects of intracoronary and i.v. administration of the inhibitor of nitric oxide synthesis, N(w)-nitro-L-arginine methyl ester (L-NAME), and those of isoproterenol, ...
Hirose Y - - 2000
BACKGROUND: The mechanisms of cardiovascular changes following acute normovolemic hemodilution (ANH) have not been fully elucidated. We tested the hypothesis that inhibition of nitric oxide synthesis attenuates ANH-induced cardiovascular responses. METHODS: We observed the effects of N(omega)-nitro-L-arginine methyl ester (L-NAME) pretreatment on ANH-induced cardiovascular responses and compared these effects with ...
Stauss H M - - 2000
Changes in arterial blood pressure (ABP) lead to changes in vascular shear stress. This mechanical stimulus increases cytosolic Ca2+ in endothelial cells, which in turn activates the endothelial isoform of the nitric oxide synthase. The subsequently formed NO reaches the adjacent vascular smooth muscle cells, where it reduces vascular resistance ...
Vapaatalo H - - 2000
A short review on the role of endothelium and nitric oxide (NO) in experimental hypertension is presented in the light of the literature and our own recent findings. Based on these data, it is concluded that even though there is a lot of evidence in favor of the primary and ...
Ghiadoni L - - 2000
Patients with essential hypertension are characterized by impaired basal and agonist-evoked nitric oxide release and increased endogenous endothelin (ET)-1-induced vasoconstriction. To assess whether candesartan, an angiotensin II type 1 receptor blocker, can improve endothelial function, we studied the changes in forearm blood flow (FBF) induced in 15 hypertensive patients and ...
Kielbasa W - - 2000
Our objective was to examine the pharmacokinetic/hemodynamic properties of inhaled isobutyl nitrite (ISBN) in rats. ISBN is one of the volatile organic nitrites that has been used primarily as a drug of abuse. Recent studies indicate, however, that these compounds may be superior to organic nitrates for cardiovascular use because ...
Gosepath K - - 2000
Two nitric oxide synthase isoforms (NOS-I and NOS-III) are present in the mammalian cochlea, and many regulatory functions of the inner ear could be mediated by NO. In this study, cochlear potentials and immunohistochemical measures were analyzed by changing the concentration of NO in the guinea pig during intracochlear and ...
Negrao C E - - 2000
The extent to which abnormal endothelium-dependent vasodilator mechanisms contribute to abnormal resting vasoconstriction and blunted reflex vasodilation seen in heart failure is unknown. The purpose of this study was to test the hypothesis that the resting and reflex abnormalities in vascular tone that characterize heart failure are mediated by abnormal ...
Kublickiene K R - - 2000
OBJECTIVE: We evaluated the role of endothelium-derived nitric oxide and endothelin 1 in the modulation of myogenic tone, norepinephrine-induced tone, and flow-mediated responses in resistance arteries from pregnant women at term. STUDY DESIGN: Arteries (approximately 200 microm at 50 mm Hg; n = 27) were dissected from myometrial biopsies obtained ...
Qiu Y - - 1999
The vascular effects of arachidonic acid (AA) were addressed in the rat perfused heart in terms of metabolic pathways and effector mechanisms. Under basal perfusion pressure, AA elicited dilator responses. However, in hearts treated with nitroarginine to eliminate nitric oxide and to elevate perfusion pressure, the predominant effect of AA ...
Datta P - - 1999
The objective of this study was to determine the circuit and cardiac effects of norepinephrine (NE) with and without endotoxin, and how these responses are modified by the inhibition of nitric oxide synthase (NOS). We anesthetized eight pigs and instrumented them for measurements of cardiac output (Q), arterial pressure (Part), ...
Bhabra M S - - 1999
BACKGROUND: Attempts to attenuate lung reperfusion injury by administration of inhaled nitric oxide have yielded conflicting results. We hypothesized that the inspired oxygen fraction may play an important role in determining the outcome of nitric oxide therapy. METHODS: Rat lungs were reperfused in a circuit incorporating a support animal either ...
Lorente J A - - 1999
OBJECTIVE: To investigate whether exogenous L-arginine, the substrate for nitric oxide synthase, modulates systemic hemodynamics in sepsis. DESIGN: Prospective, controlled study in a sheep model of sepsis. SETTING: Animal research facility in a university hospital. SUBJECTS: Adult sheep weighing between 35 and 55 kg. INTERVENTIONS: Adult sheep sedated and mechanically ...
Xie H - - 1999
BACKGROUND AND PURPOSE: Cerebral arteries develop stretch-induced myogenic tone, which plays an important role in the regulation of blood flow to the brain. Although the effect of oxidized LDL (Ox-LDL) on many aspects of the vascular endothelial and smooth muscle cell function have been extensively investigated, its influence on myogenic ...
Hayward C S - - 1999
Inhaled nitric oxide is a potent and selective pulmonary vasodilator. However, when used in patients with congestive cardiac failure, the decrease in pulmonary vascular resistance is associated with an increase in pulmonary capillary wedge pressure (PCWP). This study examined load-independent indexes of left ventricular chamber function during inhaled nitric oxide ...
Black S M - - 1999
Life-threatening increases in pulmonary vascular resistance have been noted on acute withdrawal of inhaled nitric oxide (NO), although the mechanisms remain unknown. In vitro data suggest that exogenous NO exposure inhibits endothelial NO synthase (NOS) activity. Thus the objectives of this study were to determine the effects of inhaled NO ...
Max M - - 1999
OBJECTIVE: To compare the effect of different concentrations of inhaled nitric oxide and doses of nebulized prostacyclin on hypoxia-induced pulmonary hypertension in pigs. DESIGN: Prospective, controlled animal study. SETTING: Animal research facilities of an university hospital. INTERVENTIONS: After reducing the fraction of inspired oxygen (FIO(2)) from 1.0 to 0.1, two ...
McMillon R K - - 1999
We hypothesized that pacing-induced congestive heart failure alters alpha-adrenergic constriction in intrapulmonary bronchial arteries. Cumulative dose responses to norepinephrine (NE), phenylephrine (PE), acetylcholine (ACh) and sodium nitroprusside (SNP) were determined in pressurized vessel segments. ED(50) values for NE and PE were higher for control (-5.34 +/- 0.09 and -4.27 +/- ...
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