Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Anumonwo JM
,
Horta J
,
Delmar M
,
Taffet SM
,
Jalife J
.
???displayArticle.abstract???
The proton and Zn2+ effects on the human ether-a-go-go related gene (HERG) channels were studied after expression in Xenopus oocytes and stable transfection in the mammalian L929 cell line. Experiments were carried out using the two-electrode voltage clamp at room temperature (oocytes) or the whole-cell patch clamp technique at 35 degrees C (L929 cells). In oocytes, during moderate extracellular acidification (pHo = 6.4), current activation was not shifted on the voltage axis, the time course of current activation was unchanged, but tail current deactivation was dramatically accelerated. At pHo < 6.4, in addition to accelerating deactivation, the time course of activation was slower and the midpoint voltage of current activation was shifted to more positive values. Protons and Zn2+ accelerated the kinetics of deactivation with apparent Kd values about one order of magnitude lower than for tail current inhibition. For protons, the Kd values for the effect on tail current amplitude versus kinetics were, respectively, 1.8 microM (pKa = 5.8) and 0.1 microM (pKa = 7.0). In the presence of Zn2+, the corresponding Kd values were, respectively, 1.2 mM and 169 microM. In L929 cells, acidification to pHo = 6.4 did not shift the midpoint voltage of current activation and had no effect on the time course of current activation. Furthermore, the onset and recovery of inactivation were not affected. However, the acidification significantly accelerated tail current deactivation. We conclude that protons and Zn2+ directly interact with HERG channels and that the interaction results, preferentially, in the regulation of channel deactivation mechanism.
Agus,
Divalent cations modulate the transient outward current in rat ventricular myocytes.
1991, Pubmed
Agus,
Divalent cations modulate the transient outward current in rat ventricular myocytes.
1991,
Pubmed
Anumonwo,
Electrophysiology of single heart cells from the rabbit tricuspid valve.
1990,
Pubmed
Anumonwo,
Delayed rectification in single cells isolated from guinea pig sinoatrial node.
1992,
Pubmed
Barhanin,
K(V)LQT1 and lsK (minK) proteins associate to form the I(Ks) cardiac potassium current.
1996,
Pubmed
,
Xenbase
Barrio,
Gap junctions formed by connexins 26 and 32 alone and in combination are differently affected by applied voltage.
1991,
Pubmed
,
Xenbase
Campbell,
Ionic current mechanisms generating vertebrate primary cardiac pacemaker activity at the single cell level: an integrative view.
1992,
Pubmed
Carmeliet,
Voltage- and time-dependent block of the delayed K+ current in cardiac myocytes by dofetilide.
1992,
Pubmed
Cascio,
Electrophysiologic changes in ischemic ventricular myocardium: I. Influence of ionic, metabolic, and energetic changes.
1995,
Pubmed
Chen,
Molecular basis of proton block of L-type Ca2+ channels.
1996,
Pubmed
,
Xenbase
Coulter,
Identification and molecular localization of a pH-sensing domain for the inward rectifier potassium channel HIR.
1995,
Pubmed
,
Xenbase
Curran,
A molecular basis for cardiac arrhythmia: HERG mutations cause long QT syndrome.
1995,
Pubmed
De Biasi,
Histidine substitution identifies a surface position and confers Cs+ selectivity on a K+ pore.
1993,
Pubmed
Ebihara,
Xenopus connexin38 forms hemi-gap-junctional channels in the nonjunctional plasma membrane of Xenopus oocytes.
1996,
Pubmed
,
Xenbase
Ek-Vitorín,
PH regulation of connexin43: molecular analysis of the gating particle.
1996,
Pubmed
,
Xenbase
Elinder,
Surface Charges of K channels. Effects of strontium on five cloned channels expressed in Xenopus oocytes.
1996,
Pubmed
,
Xenbase
Elinder,
Effects of gadolinium on ion channels in the myelinated axon of Xenopus laevis: four sites of action.
1994,
Pubmed
,
Xenbase
Ellinor,
Ca2+ channel selectivity at a single locus for high-affinity Ca2+ interactions.
1995,
Pubmed
,
Xenbase
FRANKENHAEUSER,
The action of calcium on the electrical properties of squid axons.
1957,
Pubmed
Gilly,
Divalent cations and the activation kinetics of potassium channels in squid giant axons.
1982,
Pubmed
Goldman,
POTENTIAL, IMPEDANCE, AND RECTIFICATION IN MEMBRANES.
1943,
Pubmed
GRAHAME,
The electrical double layer and the theory of electrocapillarity.
1947,
Pubmed
Hamill,
Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.
1981,
Pubmed
Heginbotham,
A functional connection between the pores of distantly related ion channels as revealed by mutant K+ channels.
1992,
Pubmed
,
Xenbase
Ho,
Voltage-dependent blockade of HERG channels expressed in Xenopus oocytes by external Ca2+ and Mg2+.
1998,
Pubmed
,
Xenbase
HODGKIN,
The effect of sodium ions on the electrical activity of giant axon of the squid.
1949,
Pubmed
Kiehn,
Molecular physiology and pharmacology of HERG. Single-channel currents and block by dofetilide.
1996,
Pubmed
,
Xenbase
Krafte,
Hydrogen ion modulation of Ca channel current in cardiac ventricular cells. Evidence for multiple mechanisms.
1988,
Pubmed
Kurachi,
The effects of intracellular protons on the electrical activity of single ventricular cells.
1982,
Pubmed
Liu,
Activation and inactivation kinetics of an E-4031-sensitive current from single ferret atrial myocytes.
1996,
Pubmed
Liu,
Characteristics of the delayed rectifier current (IKr and IKs) in canine ventricular epicardial, midmyocardial, and endocardial myocytes. A weaker IKs contributes to the longer action potential of the M cell.
1995,
Pubmed
McAllister,
Reconstruction of the electrical activity of cardiac Purkinje fibres.
1975,
Pubmed
McDonald,
A minK-HERG complex regulates the cardiac potassium current I(Kr).
1997,
Pubmed
,
Xenbase
Morley,
Intramolecular interactions mediate pH regulation of connexin43 channels.
1996,
Pubmed
,
Xenbase
Ono,
Role of rapidly activating delayed rectifier K+ current in sinoatrial node pacemaker activity.
1995,
Pubmed
Paquette,
Effects of divalent cations on the E-4031-sensitive repolarization current, I(Kr), in rabbit ventricular myocytes.
1998,
Pubmed
Peitzsch,
Calculations of the electrostatic potential adjacent to model phospholipid bilayers.
1995,
Pubmed
Root,
Two identical noninteracting sites in an ion channel revealed by proton transfer.
1994,
Pubmed
,
Xenbase
Sanguinetti,
Coassembly of K(V)LQT1 and minK (IsK) proteins to form cardiac I(Ks) potassium channel.
1996,
Pubmed
,
Xenbase
Sanguinetti,
A mechanistic link between an inherited and an acquired cardiac arrhythmia: HERG encodes the IKr potassium channel.
1995,
Pubmed
,
Xenbase
Sanguinetti,
Two components of cardiac delayed rectifier K+ current. Differential sensitivity to block by class III antiarrhythmic agents.
1990,
Pubmed
Schönherr,
Molecular determinants for activation and inactivation of HERG, a human inward rectifier potassium channel.
1996,
Pubmed
,
Xenbase
Smith,
The inward rectification mechanism of the HERG cardiac potassium channel.
1996,
Pubmed
Snyders,
High affinity open channel block by dofetilide of HERG expressed in a human cell line.
1996,
Pubmed
,
Xenbase
Spector,
Fast inactivation causes rectification of the IKr channel.
1996,
Pubmed
,
Xenbase
Trudeau,
HERG, a human inward rectifier in the voltage-gated potassium channel family.
1995,
Pubmed
Wang,
Delayed rectifier outward current and repolarization in human atrial myocytes.
1993,
Pubmed
Wang,
A quantitative analysis of the activation and inactivation kinetics of HERG expressed in Xenopus oocytes.
1997,
Pubmed
,
Xenbase
Warmke,
A family of potassium channel genes related to eag in Drosophila and mammals.
1994,
Pubmed
Watson,
Effect of intracellular and extracellular acidosis on sodium current in ventricular myocytes.
1995,
Pubmed
Yang,
K+ currents and K+ channel mRNA in cultured atrial cardiac myocytes (AT-1 cells).
1994,
Pubmed
Yatani,
Effect of extracellular pH on sodium current in isolated, single rat ventricular cells.
1984,
Pubmed
Zhang,
Effects of external protons on single cardiac sodium channels from guinea pig ventricular myocytes.
1991,
Pubmed
Zhou,
Properties of HERG channels stably expressed in HEK 293 cells studied at physiological temperature.
1998,
Pubmed
Zhou,
The effects of external pH on calcium channel currents in bullfrog sympathetic neurons.
1996,
Pubmed
