Consulta: subjectFacets:"Ouabain"
Registros recuperados: 10
Data/hora: 06/06/2024 02:37:04

Presynaptic neuromuscular action of a methanolic extract from the venom of Rhinella schneideri toad
Provedor de dados: 80
Autores: Rostelato-Ferreira,Sandro; Belo,Cháriston A Dal; Leite,Gildo B; Hyslop,Stephen; Rodrigues-Simioni,Léa.
BackgroundRhinella schneideri, previously known as Bufo paracnemis, is a common toad in many regions of Brazil. Its venom exerts important cardiovascular effects on humans and other animals. Although this toad venom has been the subject of intense investigations, little is known about its neuromuscular activity.MethodsThe neurotoxicity of a methanolic extract of R. schneideri venom was tested on mouse phrenic nerve-diaphragm (PND) preparations mounted for conventional twitch tension recording – in response to indirect stimulation – and for electrophysiological measurements.ResultsVenom extract (50 μg/mL) increased the muscle twitch tension in PND preparations but did not significantly alter the resting membrane potential values. Electrophysiological...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Neurotransmitter release; Ouabain; Presynaptic; Rhinella schneideri; Toad venom.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-91992014000200332

Ouabain exacerbates botulinum neurotoxin-induced muscle paralysis via progression of muscle atrophy in mice
Provedor de dados: 19
Autores: Fujikawa, Ryu; Muroi, Yoshikage; Unno, Toshihiro; Ishii, Toshiaki; 室井, 喜景; 石井, 利明.
Botulinum neurotoxin serotype A (BoNT/A) inhibits acetylcholine release at the neuromuscular junction in isolated muscles, and ouabain can partially block its effect. However, it is not clear whether ouabain attenuates BoNT/A-induced neuromuscular paralysis in vivo. In this work, we investigated the effects of ouabain on BoNT/A-induced neuromuscular paralysis in mice. Ouabain was administered to mice intraperitoneally immediately after a single injection of BoNT/A into skeletal muscle. The effects of ouabain on BoNT/A-induced muscle paralysis were assessed by quantitative monitoring of muscle tension and digit abduction via the digit abduction scoring (DAS) assay. A single administration of ouabain significantly prolonged BoNT/A-induced neuromuscular...
Palavras-chave: Ouabain; Botulinum neurotoxin; Muscle atrophy; MAFbx; MuRF-1.
Ano: 2010
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/3123

Ouabain exacerbates activation-induced cell death in human peripheral blood lymphocytes
Provedor de dados: 42
Autores: Esteves,Mabel B.; Marques-Santos,Luis F.; Affonso-Mitidieri,Ottília R.; Rumjanek,Vivian M.
Lymphocytes activated by mitogenic lectins display changes in transmembrane potential, an elevation in the cytoplasmic Ca2+ concentrations, proliferation and/or activation induced cell death. Low concentrations of ouabain (an inhibitor of Na+,K+-ATPase) suppress mitogen-induced proliferation and increases cell death. To understand the mechanisms involved, a number of parameters were analyzed using fluorescent probes and flow cytometry. The addition of 100nM ouabain to cultures of peripheral blood lymphocytes activated with 5µg/ml phytohemagglutinin (PHA) did not modify the increased expression of the Fas receptor or its ligand FasL induced by the mitogen. However, treatment with ouabain potentiated apoptosis induced by an anti-Fas agonist antibody. A...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Lymphocytes; Ouabain; PHA; Apoptosis; Membrane depolarization.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652005000200008

Ventricular performance and Na+-K+ ATPase activity are reduced early and late after myocardial infarction in rats
Provedor de dados: 56
Autores: Stefanon,I.; Cade,J.R.; Fernandes,A.A.; Ribeiro Junior,R.F.; Targueta,G.P.; Mill,J.G.; Vassallo,D.V.
Myocardial infarction leads to compensatory ventricular remodeling. Disturbances in myocardial contractility depend on the active transport of Ca2+ and Na+, which are regulated by Na+-K+ ATPase. Inappropriate regulation of Na+-K+ ATPase activity leads to excessive loss of K+ and gain of Na+ by the cell. We determined the participation of Na+-K+ ATPase in ventricular performance early and late after myocardial infarction. Wistar rats (8-10 per group) underwent left coronary artery ligation (infarcted, Inf) or sham-operation (Sham). Ventricular performance was measured at 3 and 30 days after surgery using the Langendorff technique. Left ventricular systolic pressure was obtained under different ventricular diastolic pressures and increased extracellular Ca2+...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Heart failure; Ouabain; Na+-K+ ATPase; Myocardial infarction; Calcium handling.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001000005

Hypertensive effects of the iv administration of picomoles of ouabain
Provedor de dados: 56
Autores: Padilha,A.S.; Salaices,M.; Vassallo,D.V.; Batista,P.R.; Siman,F.D.M.
Ouabain, an endogenous digitalis compound, has been detected in nanomolar concentrations in the plasma of several mammals and is associated with the development of hypertension. In addition, plasma ouabain is increased in several hypertension models, and the acute or chronic administration of ouabain increases blood pressure in rodents. These results suggest a possible association between ouabain and the genesis or development and maintenance of arterial hypertension. One explanation for this association is that ouabain binds to the α-subunit of the Na+ pump, inhibiting its activity. Inhibition of this pump increases intracellular Na+, which reduces the activity of the sarcolemmal Na+/Ca2+ exchanger and thereby reduces Ca2+ extrusion. Consequently,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ouabain; Hypertension; Vascular reactivity; Renin-angiotensin system.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011000900015

Na,K-ATPase: a molecular target for Leptospira interrogans endotoxin
Provedor de dados: 56
On the basis of our report that a glycolipoprotein fraction (GLP) extracted from Leptospira interrogans contains a potent inhibitor of renal Na,K-ATPase, we proposed that GLP-induced inhibition of Na,K-ATPase might be the primary cellular defect in the physiopathology of leptospirosis. The present study was designed to test this hypothesis by determining whether or not 1) GLP inhibits all the isoforms of Na,K-ATPase which are expressed in the tissues affected by leptospirosis, 2) Na,K-ATPase from leptospirosis-resistant species, such as the rat, is sensitive to GLP, 3) GLP inhibits Na,K-ATPase from intact cells, and 4) GLP inhibits ouabain-sensitive H,K-ATPase. The results indicate that in the rabbit, a leptospirosis-sensitive species, GLP inhibits with...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Na/K-ATPase; H/K-ATPase; Na/K-ATPase isoforms; Rubidium transport; Leptospirosis; Ouabain.
Ano: 1997
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000200009

Effects of small doses of ouabain on the arterial blood pressure of anesthetized hypertensive and normotensive rats
Provedor de dados: 56
Autores: Rossoni,L.V.; Pinto,V.D.; Vassallo,D.V.
Ouabain increases vascular resistance and may induce hypertension by inhibiting the Na+ pump. The effects of 0.18 and 18 µg/kg, and 1.8 mg/kg ouabain pretreatment on the phenylephrine (PHE; 0.1, 0.25 and 0.5 µg, in bolus)-evoked pressor responses were investigated using anesthetized normotensive (control and uninephrectomized) and hypertensive (1K1C and DOCA-salt treated) rats. Treatment with 18 µg/kg ouabain increased systolic and diastolic blood pressure in all groups studied. However, the magnitude of this increase was larger for the hypertensive 1K1C and DOCA-salt rats than for normotensive animals, while the pressor effect of 0.18 µg/kg ouabain was greater only in DOCA-salt rats. A very large dose (1.8 mg/kg) produced toxic effects on the normotensive...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Pressor reactivity; Ouabain; Phenylephrine; 1K1C rats; DOCA-salt; Uninephrectomy.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000800014

A key role for Na+/K+-ATPase in the endothelium-dependent oscillatory activity of mouse small mesenteric arteries
Provedor de dados: 56
Autores: Giachini,F.R.C.; Carneiro,F.S.; Lima,V.V.; Carneiro,Z.N.; Brands,M.W.; Webb,R.C.; Tostes,R.C.
Oscillatory contractile activity is an inherent property of blood vessels. Various cellular mechanisms have been proposed to contribute to oscillatory activity. Mouse small mesenteric arteries display a unique low frequency contractile oscillatory activity (1 cycle every 10-12 min) upon phenylephrine stimulation. Our objective was to identify mechanisms involved in this peculiar oscillatory activity. First-order mesenteric arteries were mounted in tissue baths for isometric force measurement. The oscillatory activity was observed only in vessels with endothelium, but it was not blocked by L-NAME (100 µM) or indomethacin (10 µM), ruling out the participation of nitric oxide and prostacyclin, respectively, in this phenomenon. Oscillatory activity was not...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Oscillatory activity; Na+/K+-ATPase pump; Ouabain; Small mesenteric arteries.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001100010

A low concentration of ouabain (0.18 µg/kg) enhances hypertension in spontaneously hypertensive rats by inhibiting the Na+ pump and activating the renin-angiotensin system
Provedor de dados: 56
Autores: Siman,F.D.M.; Stefanon,I.; Vassallo,D.V.; Padilha,A.S.
We investigated the effects of low ouabain concentrations on systolic (SAP) and diastolic (DAP) arterial pressures and on pressor reactivity in 3-month-old male spontaneously hypertensive rats (SHR). Arterial blood pressure (BP) and pressor reactivity to phenylephrine (PHE) were investigated before and after 0.18 μg/kg ouabain administration (N = 6). The influence of hexamethonium (N = 6), canrenone (N = 6), enalapril (N = 6), and losartan (N = 6) on ouabain actions was evaluated. Ouabain increased BP (SAP: 137 ± 5.1 to 150 ± 4.7; DAP: 93.7 ± 7.7 to 116 ± 3.5 mmHg; P&lt;0.05) but did not change PHE pressor reactivity. Hexamethonium reduced basal BP in control but not in ouabain-treated rats. However, hexamethonium + ouabain increased DAP sensitivity to...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ouabain; Hypertension; Na+ pump; Renin-angiotensin system.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2010000800010

Effects of ouabain on vascular reactivity
Provedor de dados: 56
Ouabain is an endogenous substance occurring in the plasma in the nanomolar range, that has been proposed to increase vascular resistance and induce hypertension. This substance acts on the&lt;FONT FACE="Symbol"&gt; a&lt;/font&gt;-subunit of Na+,K+-ATPase inhibiting the Na+-pump activity. In the vascular smooth muscle this effect leads to intracellular Na+ accumulation that reduces the activity of the Na+/Ca2+ exchanger and to an increased vascular tone. It was also suggested that circulating ouabain, even in the nanomolar range, sensitizes the vascular smooth muscle to vasopressor substances. We tested the latter hypothesis by studying the effects of ouabain in the micromolar and nanomolar range on phenylephrine (PE)-evoked pressor responses. The...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Ouabain; Na+-pump; Hypertension; Rat tail vascular bed perfusion; Arterial blood pressure; Vascular reactivity; Phenylephrine.
Ano: 1997
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000400016