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Registros recuperados: 12 | |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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Registros recuperados: 12 | |
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