Consulta: creatorFacets:"Vassallo,D.V."
Registros recuperados: 15
Data/hora: 02/06/2024 17:29:41

Effects of mercury on the arterial blood pressure of anesthetized rats
Provedor de dados: 56
Autores: Rossoni,L.V.; Amaral,S.M.C.; Vassallo,P.F.; França,A.; Oliveira,E.M.; Varner,K.J.; Mill,J.G.; Vassallo,D.V.
The available data suggests that hypotension caused by Hg2+ administration may be produced by a reduction of cardiac contractility or by cholinergic mechanisms. The hemodynamic effects of an intravenous injection of HgCl2 (5 mg/kg) were studied in anesthetized rats (N = 12) by monitoring left and right ventricular (LV and RV) systolic and diastolic pressures for 120 min. After HgCl2 administration the LV systolic pressure decreased only after 40 min (99 ± 3.3 to 85 ± 8.8 mmHg at 80 min). However, RV systolic pressure increased, initially slowly but faster after 30 min (25 ± 1.8 to 42 ± 1.6 mmHg at 80 min). Both right and left diastolic pressures increased after HgCl2 treatment, suggesting the development of diastolic ventricular dysfunction. Since HgCl2...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mercury; Arterial blood pressure; Ventricular pressure; Pulmonary circulation; Diastolic dysfunction; Cholinergic activity.
Ano: 1999
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999000800009

Toxic effects of mercury, lead and gadolinium on vascular reactivity
Provedor de dados: 56
Autores: Vassallo,D.V.; Simões,M.R.; Furieri,L.B.; Fioresi,M.; Fiorim,J.; Almeida,E.A.S.; Angeli,J.K.; Wiggers,G.A.; Peçanha,F.M.; Salaices,M.
Heavy metals have been used in a wide variety of human activities that have significantly increased both professional and environmental exposure. Unfortunately, disasters have highlighted the toxic effects of metals on different organs and systems. Over the last 50 years, the adverse effects of chronic lead, mercury and gadolinium exposure have been underscored. Mercury and lead induce hypertension in humans and animals, affecting endothelial function in addition to their other effects. Increased cardiovascular risk after exposure to metals has been reported, but the underlying mechanisms, mainly for short periods of time and at low concentrations, have not been well explored. The presence of other metals such as gadolinium has raised concerns about...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Heavy metal toxicity; Vascular reactivity; Mercury; Lead; Gadolinium.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011000900016

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

Correction Braz J Med Biol Res 1994; 27(11): 2667-2679 - Analysis of right and left ventricular performance of the rat heart with chronic myocardial infarction
Provedor de dados: 56
Autores: Stefanon,I.; Auxiliadora-Martins,M.; Vassallo,D.V.; Mill,J.G.
Tipo: Info:eu-repo/semantics/article
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000900015

A single resistance exercise session improves myocardial contractility in spontaneously hypertensive rats
Provedor de dados: 56
Autores: Fernandes,A.A.; Faria,T. de O.; Ribeiro Júnior,R.F.; Costa,G.P.; Marchezini,B.; Silveira,E.A.; Angeli,J.K.; Stefanon,I.; Vassallo,D.V.; Lizardo,J.H.
Resistance training evokes myocardial adaptation; however, the effects of a single resistance exercise session on cardiac performance are poorly understood or investigated. This study aimed to investigate the effects of a single resistance exercise session on the myocardial contractility of spontaneously hypertensive rats (SHRs). Male 3-month-old SHRs were divided into two groups: control (Ct) and exercise (Ex). Control animals were submitted to sham exercise. Blood pressure was measured in conscious rats before the exercise session to confirm the presence of arterial hypertension. Ten minutes after the exercise session, the animals were anesthetized and killed, and the hearts were removed. Cardiac contractility was evaluated in the whole heart by the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cardiac; Contractility; Myocardium; Proteins; Resistance exercise.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2015000900813

Differences in functional and structural properties of segments of the rat tail artery
Provedor de dados: 56
Autores: Souza,F.M.; Padilha,A.S.; Stefanon,I.; Vassallo,D.V.
The investigation of resistance vessels is generally costly and difficult to execute. The present study investigated the diameters and the vascular reactivity of different segments of the rat tail artery (base, middle, and tail end) of 30 male Wister rats (EPM strain) to characterize a conductance or resistance vessel, using a low-cost simple technique. The diameters (mean ± SEM) of the base and middle segments were 471 ± 4.97 and 540 ± 8.39 µm, respectively, the tail end was 253 ± 2.58 µm. To test reactivity, the whole tail arteries or segments were perfused under constant flow and the reactivity to phenylephrine (PHE; 0.01-300 µg) was evaluated before and after removal of the endothelium or drug administration. The maximal response (Emax) and sensitivity...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Rat tail artery; Phenylephrine; Resistance artery; Endothelium; Conductance artery.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008000500011

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

Acute exposure to lead increases myocardial contractility independent of hypertension development
Provedor de dados: 56
Autores: Fioresi,M.; Furieri,L.B.; Simões,M.R.; Ribeiro Junior,R.F.; Meira,E.F.; Fernandes,A.A.; Stefanon,I.; Vassallo,D.V.
We studied the effects of the acute administration of small doses of lead over time on hemodynamic parameters in anesthetized rats to determine if myocardial contractility changes are dependent or not on the development of hypertension. Male Wistar rats received 320 µg/kg lead acetateiv once, and their hemodynamic parameters were measured for 2 h. Cardiac contractility was evaluated in vitro using left ventricular papillary muscles as were Na+,K+-ATPase and myosin Ca2+-ATPase activities. Lead increased left- (control: 112 ± 3.7 vs lead: 129 ± 3.2 mmHg) and right-ventricular systolic pressures (control: 28 ± 1.2vs lead: 34 ± 1.2 mmHg) significantly without modifying heart rate. Papillary muscles were exposed to 8 µM lead acetate and evaluated 60 min later....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Lead; Myocardial contractility; Ventricular pressure.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2013000200178

Acute lead-induced vasoconstriction in the vascular beds of isolated perfused rat tails is endothelium-dependent
Provedor de dados: 56
Autores: Silveira,E.A.; Lizardo,J.H.F.; Souza,L.P.; Stefanon,I.; Vassallo,D.V.
Chronic lead exposure induces hypertension in humans and animals, affecting endothelial function. However, studies concerning acute cardiovascular effects are lacking. We investigated the effects of acute administration of a high concentration of lead acetate (100 µΜ) on the pressor response to phenylephrine (PHE) in the tail vascular bed of male Wistar rats. Animals were anesthetized with sodium pentobarbital and heparinized. The tail artery was dissected and cannulated for drug infusion and mean perfusion pressure measurements. Endothelium and vascular smooth muscle relaxation were tested with acetylcholine (5 µg/100 µL) and sodium nitroprusside (0.1 µg/100 µL), respectively, in arteries precontracted with 0.1 µM PHE. Concentration-response curves to PHE...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Lead acetate; Vascular reactivity; Endothelium; Hypertension.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2010000500011

The left ventricular contractility of the rat heart is modulated by changes in flow and a1-adrenoceptor stimulation
Provedor de dados: 56
Autores: Vassallo,P.F.; Stefanon,I.; Rossoni,L.V.; Tucci,P.J.F.; Vassallo,D.V.
Myocardial contractility depends on several mechanisms such as coronary perfusion pressure (CPP) and flow as well as on &lt;FONT FACE="Symbol"&gt;a&lt;/font&gt;1-adrenoceptor stimulation. Both effects occur during the sympathetic stimulation mediated by norepinephrine. Norepinephrine increases force development in the heart and produces vasoconstriction increasing arterial pressure and, in turn, CPP. The contribution of each of these factors to the increase in myocardial performance needs to be clarified. Thus, in the present study we used two protocols: in the first we measured mean arterial pressure, left ventricular pressure and rate of rise of left ventricular pressure development in anesthetized rats (N = 10) submitted to phenylephrine (PE)...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Myocardial performance; Coronary perfusion pressure; Coronary flow; Phenylephrine.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001000019

Lead reduces tension development and the myosin ATPase activity of the rat right ventricular myocardium
Provedor de dados: 56
Autores: Vassallo,D.V.; Lebarch,E.C.; Moreira,C.M.; Wiggers,G.A.; Stefanon,I.
Lead (Pb2+) poisoning causes hypertension, but little is known regarding its acute effects on cardiac contractility. To evaluate these effects, force was measured in right ventricular strips that were contracting isometrically in 45 male Wistar rats (250-300 g) before and after the addition of increasing concentrations of lead acetate (3, 7, 10, 30, 70, 100, and 300 µM) to the bath. Changes in rate of stimulation (0.1-1.5 Hz), relative potentiation after pauses of 15, 30, and 60 s, effect of Ca2+ concentration (0.62, 1.25, and 2.5 mM), and the effect of isoproterenol (20 ng/mL) were determined before and after the addition of 100 µM Pb2+. Effects on contractile proteins were evaluated after caffeine treatment using tetanic stimulation (10 Hz) and measuring...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Lead; Right ventricular strips; Contraction; Heart; Myosin ATPase activity.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008000900008

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 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

Eucalyptol, an essential oil, reduces contractile activity in rat cardiac muscle
Provedor de dados: 56
Autores: Soares,M.C.M.S.; Damiani,C.E.N.; Moreira,C.M.; Stefanon,I.; Vassallo,D.V.
Eucalyptol is an essential oil that relaxes bronchial and vascular smooth muscle although its direct actions on isolated myocardium have not been reported. We investigated a putative negative inotropic effect of the oil on left ventricular papillary muscles from male Wistar rats weighing 250 to 300 g, as well as its effects on isometric force, rate of force development, time parameters, post-rest potentiation, positive inotropic interventions produced by Ca2+ and isoproterenol, and on tetanic tension. The effects of 0.3 mM eucalyptol on myosin ATPase activity were also investigated. Eucalyptol (0.003 to 0.3 mM) reduced isometric tension, the rate of force development and time parameters. The oil reduced the force developed by steady-state contractions (50%...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Eucalyptol; Myocardial contractility; Calcium; Isoproterenol; Tetanic tension.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005000300017

Gadolinium increases the vascular reactivity of rat aortic rings
Provedor de dados: 56
Autores: Angeli,J.K.; Ramos,D.B.; Casali,E.A.; Souza,D.O.G.; Sarkis,J.J.F.; Stefanon,I.; Vassallo,D.V.; Fürstenau,C.R.
Gadolinium (Gd) blocks intra- and extracellular ATP hydrolysis. We determined whether Gd affects vascular reactivity to contractile responses to phenylephrine (PHE) by blocking aortic ectonucleoside triphosphate diphosphohydrolase (E-NTPDase). Wistar rats of both sexes (260-300 g, 23 females, 7 males) were used. Experiments were performed before and after incubation of aortic rings with 3 µM Gd. Concentration-response curves to PHE (0.1 nM to 0.1 mM) were obtained in the presence and absence of endothelium, after incubation with 100 µM L-NAME, 10 µM losartan, or 10 µM enalaprilat. Gd significantly increased the maximum response (control: 72.3 ± 3.5; Gd: 101.3 ± 6.4%) and sensitivity (control: 6.6 ± 0.1; Gd: 10.5 ± 2.8%) to PHE. To investigate the blockade...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Gadolinium; E-NTPDase; Adenosine; Angiotensin II; AT1receptor.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011000500010