OuabainSodiumSodium-Potassium-Exchanging ATPaseStrophanthidinCardiac GlycosidesPotassiumSodium IsotopesBiological Transport, ActivePurkinje FibersRubidiumDysprosiumSodium ChannelsMembrane PotentialsCardenolidesLithiumIon ChannelsBufanolidesVeratrineCalciumVeratridineDigoxinPhotometryIntracellular FluidMonensinAmilorideMyocardial ContractionErythrocytesSodium-Hydrogen AntiporterTetrodotoxinSodium ChlorideExtracellular SpaceBufo bufoAnuraSheepRubidium RadioisotopesOpossumsMyocardiumDigitoxigeninHeart Conduction SystemPapillary MusclesSodium-Calcium ExchangerCardanolidesSodium Channel BlockersGuinea PigsBiological TransportKineticsCell Membrane PermeabilityIon TransportAdenosine TriphosphateBenzofuransSaponinsAction PotentialsHydrogen-Ion ConcentrationMagnetic Resonance SpectroscopySodium, DietaryCell MembraneDogsHeartTime FactorsCardiac Complexes, PrematureDigitalisOsmolar ConcentrationAcetanilidesEthers, CyclicLidocaineKidney Tubules, ProximalProton Pump InhibitorsMagnesiumMicroelectrodesElectrophysiologyPerfusionDigitoxinHypertensionRats, Sprague-DawleySodium RadioisotopesAcrylamidesTemperatureIon PumpsVanadium4-NitrophenylphosphataseCells, CulturedHeart VentriclesAdenosine TriphosphatasesPotassium IsotopesRats, Inbred StrainsEnzyme InhibitorsInfusion PumpsElectric StimulationIntracellular MembranesModels, BiologicalErythrocyte MembraneKidneyKidney MedullaNorepinephrineCardiotonic AgentsRadioisotopesFluorescent DyesRabbitsIon ExchangeNeurons