Action PotentialsMembrane PotentialsMembranesCell MembraneMembrane LipidsIntracellular MembranesMembranes, ArtificialElectrophysiologyPatch-Clamp TechniquesCalciumTetrodotoxinElectric StimulationErythrocyte MembraneMembrane FluidityPotassiumGuinea PigsCell Membrane PermeabilityNeuronsPotassium ChannelsSodium ChannelsElectric ConductivityBasement MembraneSodiumNeural ConductionVentricular FunctionHeartTime FactorsAxonsHeart Conduction SystemIon ChannelsMicroelectrodesSynaptic Transmission4-AminopyridinePapillary MusclesDendritesPyramidal CellsDogsHeart VentriclesSynapsesTetraethylammonium CompoundsCells, CulturedMembrane Transport ProteinsPotassium Channel BlockersPurkinje FibersRabbitsMembrane GlycoproteinsRats, Sprague-DawleyPotassium Channels, Voltage-GatedSynaptic MembranesMicroscopy, ElectronCalcium ChannelsModels, BiologicalMyocytes, CardiacLipid BilayersTetraethylammoniumIon Channel GatingRefractory Period, ElectrophysiologicalSodium Channel BlockersModels, CardiovascularAnti-Arrhythmia AgentsExcitatory Postsynaptic PotentialsMitochondrial MembranesMyocardiumArrhythmias, CardiacRats, WistarCell LineProtein TransportEvoked PotentialsDelayed Rectifier Potassium ChannelsModels, NeurologicalCalcium SignalingNeurons, AfferentCalcium Channels, L-TypeFluorescent DyesKineticsAnuraMyocardial ContractionMotor NeuronsComputer SimulationHeart AtriaHydrogen-Ion ConcentrationProtein BindingCalcium Channel BlockersLiposomesMutationHippocampusSinoatrial NodeDose-Response Relationship, DrugAtrial FunctionTemperatureAnimals, NewbornBariumVoltage-Sensitive Dye ImagingElectrophysiological PhenomenaProtein Structure, TertiaryCarrier ProteinsMusclesCell FractionationMicroscopy, FluorescenceEndocardium