Ouabain-induced hypertension enhances left ventricular contractility in rats

Rossoni, Luciana Venturini; Xavier, Fabiano E.; Moreira, Carlos Heitor Cunha; Falcochio, Diego Figueira; Amanso, Angélica M.; Tanoue, Carolina U.; Carvalho, Carla Roberta de Oliveira; Vassallo, Dalton Valentim

doi:10.1016/j.lfs.2006.04.017

Cited by 19 publications

(25 citation statements)

References 38 publications

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“…These in-vivo effects are associated with significant enrichment of a1, b1, ga Naþ,Kþ-ATPase subunits together with Src and EGFr in isolated renal caveolae membranes, and with activation of ERK1/2 [4]. On the contrary, Rossoni et al [27] showed that treatment of rats with a higher concentration of ouabain (8 mg/day) for a shorter period (5 weeks) induced hypertension without LV hypertrophy or impaired function of the sarcoplasmic reticulum. These authors also showed positive inotropic and lusitropic effects on the hearts of ouabain-treated rats, which were associated with an increment in the activity of myosin ATPase and in the expression of the catalytic subunit of the Naþ,Kþ-ATPase.…”

Section: Discussionmentioning

confidence: 98%

Left ventricular geometry and endogenous ouabain in a Flemish population

Kuznetsova

Manunta

Casamassima³

et al. 2009

Journal of Hypertension

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Background Endogenous ouabain, an endogenous digitalis-like steroid, is synthesized in the adrenal glands and possibly in the hypothalamus. In vitro and in vivo, endogenous ouabain triggers growth and proliferation of cardiomyocytes.Objective We therefore investigated the association between left ventricular structure and function and plasma endogenous ouabain in a general population.Methods We randomly recruited 536 individuals from a general population (50.7% women, mean age 53.1 years). Measurements included echocardiographic left ventricular structure and function, blood pressure, plasma endogenous ouabain, and the 24-h urinary excretion of sodium.Results The geometric mean plasma endogenous ouabain was 95.5 pmol/l (interquartile range 79.4-120.2 pmol/l). We expressed effect sizes for a 1-SD increase in plasma endogenous ouabain (0.21 on the logarithmic scale), while accounting for important covariables. For a 1-SD increment in plasma endogenous ouabain, SBP, left ventricular posterior wall, the interventricular septum, and relative wall thickness increased by 1.59 mmHg (P U 0.009), 0.138 mm (P U 0.003), 0.152 mm (P U 0.013), and 0.71 T 10 S2 (P U 0.008), respectively. In a sensitivity analysis, involving 431 individuals aged 29-71 years (10-90th percentile interval), a 1-SD increase in plasma endogenous ouabain was associated with opposite trends in ejection fraction (R0.90%, P U 0.005) and left ventricular systolic longitudinal strain (S0.48%, P U 0.011). Moreover, in individuals whose sodium excretion was above median (160 mmol/24 h), the aforementioned associations reached a higher level of statistical significance.Conclusion Our population-based study suggested that endogenous ouabain might have a trophic effect on the myocardium, independent of blood pressure and other covariables. The clinical implication of these findings remains to be elucidated.

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Section: Discussionmentioning

confidence: 98%

Left ventricular geometry and endogenous ouabain in a Flemish population

Kuznetsova

Manunta

Casamassima³

et al. 2009

Journal of Hypertension

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“…Tissue homogenates were analyzed by Western blotting according to previously described protocols 5 to compare the protein expression of SERCA2, phospholamban (PLB), phosphoSer 16 -PLB and NCX in all experimental groups. Samples of noninfarcted myocardium were rapidly frozen at -70 o C. Tissues were homogenized in ice-cold extraction buffer (Tris 50 mM, EDTA 1 mM and sacarose 250 mM, pH 7.4) using Polytron (Polytron® PT2100, Kinematica AG, Littau, LU, SWI).…”

Section: Protein Expression Of Serca2 Phospholamban and Ncxmentioning

confidence: 99%

“…Thus, changes in rate and rhythm are frequently used as experimental maneuvers to evaluate the behavior or disclose abnormalities of Ca 2+ kinetics on the excitation-contraction coupling 3 . Accordingly, post-rest contraction (PRC) allows indirect evaluation of the SR function 2,4,5 . In the myocardium of normal rats, PRC is potentiated due to the additional Ca 2+ accumulated in the SR during the pause due to SR Ca 2+ -ATPase (SERCA2) activity and the increased fractional Ca 2+ release 2,5 upon activation.…”

Section: Introductionmentioning

confidence: 99%

“…Accordingly, post-rest contraction (PRC) allows indirect evaluation of the SR function 2,4,5 . In the myocardium of normal rats, PRC is potentiated due to the additional Ca 2+ accumulated in the SR during the pause due to SR Ca 2+ -ATPase (SERCA2) activity and the increased fractional Ca 2+ release 2,5 upon activation. On the other hand, PRC is negatively modulated by the Ca 2+ efflux throughout the Na + / Ca 2+ exchanger (NCX) 1,2,6,7 .…”

Section: Introductionmentioning

confidence: 99%

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Remodelamento miocárdico após grandes infartos converte potenciação pós-pausa em decaimento da força em ratos

Bocalini¹,

Santos²,

Antônio³

et al. 2012

Arq. Bras. Cardiol.

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“…Furthermore, increased blood pressure as well as isometric force and myosin ATPase activity was observed after 5 weeks of ouabain treatment [19]. Although it is already known that ouabain inhibits NKA activity, some reports have brought up the evidence in which low-dose ouabain can activate the NKA instead of inhibiting it [20,21].…”

Section: Introductionmentioning

confidence: 98%