Ouabain inhibition of the sodium‐potassium pump: estimation of ED50 in different types of human leucocytes in vitro.

Møller, Bjarne Nue; Vaag, Allan; Johansen, Torben

doi:10.1111/j.1365-2125.1990.tb03607.x

Cited by 7 publications

(7 citation statements)

References 12 publications

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“…Employing the obtained parameters in the ion transport model, we predict temporal changes in the cytoplasm conductivity of CHO cells. We verify the model predictions by comparing its results with measured cytoplasm conductivity of healthy and pump-inhibited CHO cells using Ouabain 27,28 . Measurement of cytoplasm conductivity is performed at a single cell level using a dielectrophoresis (DEP) cytometer 29–31 .…”

Section: Introductionmentioning

confidence: 86%

Quantitative Model for Ion Transport and Cytoplasm Conductivity of Chinese Hamster Ovary Cells

Fazelkhah

Braasch

Afshar

et al. 2018

Sci Rep

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In mammalian cells cytoplasm ion concentrations and hence cytoplasm conductivity is an important indicator of their physiological state. Changes in the cytoplasm conductivity has been associated with physiological changes such as progression of cancer and apoptosis. In this work, a model that predicts the effects of physiological changes in ion transport on the cytoplasm conductivity of Chinese hamster ovary (CHO) cells is demonstrated. We determined CHO-specific model parameters, Na+/K+ ATPase pumps and ion channels densities, using a flux assay approach. The obtained sodium (PNa), potassium (PK) and chloride (PCl) permeability and Na+/K+ ATPase pump density were estimated to be 5.6 × 10−8 cm/s, 5.6 × 10−8 cm/s, 3.2 × 10−7 cm/s and 2.56 × 10−11 mol/cm2, respectively. The model was tested by comparing the model predictions with the experimentally determined temporal changes in the cytoplasm conductivity of Na+/K+ ATPase pump inhibited CHO cells. Cells’ Na+/K+ ATPase pumps were inhibited using 5 mM Ouabain and the temporal behavior of their cytoplasm conductivity was measured using dielectrophoresis cytometry. The measured results are in close agreement with the model-calculated values. This model will provide insight on the effects of processes such as apoptosis or external media ion concentration on the cytoplasm conductivity of mammalian cells.

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Section: Introductionmentioning

confidence: 86%

Quantitative Model for Ion Transport and Cytoplasm Conductivity of Chinese Hamster Ovary Cells

Fazelkhah

Braasch

Afshar

et al. 2018

Sci Rep

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“…Uptake of "Rb was measured as previously described (Moller et al, 1990). Purified T lymphocytes (1.5 x lo7/ ml) were incubated in PBS in the presence or absence of 1 mM ouabain for 15 min and pulsed with "Rb (10 pCi/ml) for 15 min.…”

Section: Measurement Of 86rb Uptakementioning

confidence: 99%

Ouabain induces inhibition of the progression phase in human T‐cell proliferation

Brodie

Tordai

Saloga

et al. 1995

Journal Cellular Physiology

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Ouabain, a specific inhibitor of the Na-K ATPase, has been shown to exert immunosuppressive effects. The goals of this study were to define the stage of the proliferative response which is sensitive to ouabain and to correlate the inhibitory action of ouabain on cell proliferation with its effect on Na-K ATPase activity. We found that ouabain inhibited T-cell proliferation in a dose-dependent manner and this inhibition was similar in CD4+ and CD8+ T cells. To define the role of the Na-K ATPase in early activation of T lymphocytes, we examined the effects of ouabain on the induction of competence (acquisition of responsiveness to interleukin (IL)-2 or IL-4) by phytohemagglutinin (PHA) or the combination of phorbol dibutyrate/ionomycin. Ouabain, at concentrations that completely inhibited the enzyme activity, did not interfere with the induction of competence, suggesting that although activated cells express increased activity of Na-K ATPase, this enzyme activity does not play a role in early activation pathways. In contrast, ouabain inhibited the progression phase to DNA synthesis in a dose-dependent manner even at concentrations that had little or no effect on Na-K ATPase activity. This inhibition was not due to a decrease in the production of IL-2 but rather to an inhibition of the expression of the p55 and p75 subunits of the IL-2 receptor (IL-2R). The inhibition of p55 appeared to occur at the mRNA level. These results indicate that the activity of the Na-K ATPase is not essential for the induction of competence or early activation. On the other hand, inhibition of cell proliferation and transcription of IL-2R subunits by low concentrations of ouabain may be related to changes in intracellular K+ concentrations or to inhibition of membranal phospholipid metabolism secondary to alteration in Na-K ATPase activity.

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“…As Oua has been commonly adopted as a standard NKA inhibitor, we treated Cav1.2-CHO and hESC-CMs with 10 µM Oua which is known to completely block the NKA activity 20, 22 . As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…As it is well-received that NKA-inhibition by CGs is the cause of the increase cytosolic [Ca 2+ ] i and CDI 1 , 3 – 5 , we further validated the role of NKA inhibition in the inhibitory effect of BF and CBG on I Ca,L . As Oua has been commonly adopted as a standard NKA inhibitor, we treated Cav1.2-CHO and hESC-CMs with 10 µM Oua which is known to completely block the NKA activity 20 , 22 . As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The dissociation between inotropic and proarrhythmic actions of CGs indicates that the proarrhythmic effects of CGs may not result solely from NKA inhibition 18 – 21 . For example, Chan Su (toad venom) and its key ingredient BF have demonstrated more potent cardiotoxicity over Oua as additional proarrhythmic effects were achieved by Chan Su or BF after the Na + /K + -ATPase activity was fully blocked by Oua 20 , 22 .…”

Section: Introductionmentioning

confidence: 99%

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Identification of Na+/K+-ATPase inhibition-independent proarrhythmic ionic mechanisms of cardiac glycosides

Koh

Chung

et al. 2017

Sci Rep

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The current study explored the Na+/K+-ATPase (NKA) inhibition-independent proarrhythmic mechanisms of cardiac glycosides (CGs) which are well-known NKA inhibitors. With the cytosolic Ca2+ chelated by EGTA and BAPTA or extracellular Ca2+ replaced by Ba2+, effects of bufadienolides (bufalin (BF) and cinobufagin (CBG)) and cardenolides (ouabain (Oua) and pecilocerin A (PEA)) on the L-type calcium current (I Ca,L) were recorded in heterologous expression Cav1.2-CHO cells and human embryonic stem cell-derived cardiomyocytes (hESC-CMs). BF and CBG demonstrated a concentration-dependent (0.1 to 100 µM) I Ca,L inhibition (maximal ≥50%) without and with the NKA activity blocked by 10 µM Oua. BF significantly shortened the action potential duration at 1.0 µM and shortened the extracellular field potential duration at 0.01~1.0 µM. On the other hand, BF and CBG at 100 µM demonstrated a strong inhibition (≥40%) of the rapidly activating component of the delayed rectifier K+ current (I Kr) in heterologous expression HEK293 cells and prolonged the APD of the heart of day-3 Zebrafish larva with disrupted rhythmic contractions. Moreover, hESC-CMs treated with BF (10 nM) for 24 hours showed moderate yet significant prolongation in APD90. In conclusion, our data indicate that CGs particularly bufadienolides possess cytosolic [Ca2+]i- and NKA inhibition- independent proarrhythmic potential through I Ca,L and I Kr inhibitions.

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Ouabain inhibition of the sodium‐potassium pump: estimation of ED50 in different types of human leucocytes in vitro.

Cited by 7 publications

References 12 publications

Quantitative Model for Ion Transport and Cytoplasm Conductivity of Chinese Hamster Ovary Cells

Quantitative Model for Ion Transport and Cytoplasm Conductivity of Chinese Hamster Ovary Cells

Ouabain induces inhibition of the progression phase in human T‐cell proliferation

Identification of Na+/K+-ATPase inhibition-independent proarrhythmic ionic mechanisms of cardiac glycosides

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