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A quantitative analysis of the activation and inactivation kinetics of HERG expressed in Xenopus oocytes.
Wang S
,
Liu S
,
Morales MJ
,
Strauss HC
,
Rasmusson RL
.
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1. The human ether à-go-go-related gene (HERG) encodes a K+ channel that is believed to be the basis of the delayed rectified current, IKr, in cardiac muscle. We studied HERG expressed in Xenopus oocytes using a two-electrode and cut-open oocyte clamp technique with [K+]0 of 2 and 98 mM. 2. The time course of activation of the channel was measured using an envelope of tails protocol and demonstrated that activation of the heterologously expressed HERG current (IHERG) was sigmoidal in onset. At least three closed states were required to reproduce the sigmoid time course. 3. The voltage dependence of the activation process and its saturation at positive voltages suggested the existence of at least one relatively voltage-insensitive step. A three closed state activation model with a single voltage-insensitive intermediate closed state was able to reproduce the time and voltage dependence of activation, deactivation and steady-state activation. Activation was insensitive to changes in [K+]0. 4. Both inactivation and recovery time constants increased with a change of [K+]0 from 2 to 98 mM. Steady-state inactivation shifted by approximately 30 mV in the depolarized direction with a change from 2 to 98 mM K+0. 5. Simulations showed that modulation of inactivation is a minimal component of the increase of this current by [K+]0, and that a large increase in total conductance must also occur.
Anumonwo,
Delayed rectification in single cells isolated from guinea pig sinoatrial node.
1992, Pubmed
Anumonwo,
Delayed rectification in single cells isolated from guinea pig sinoatrial node.
1992,
Pubmed
Balser,
Time-dependent outward current in guinea pig ventricular myocytes. Gating kinetics of the delayed rectifier.
1990,
Pubmed
Baukrowitz,
Modulation of K+ current by frequency and external [K+]: a tale of two inactivation mechanisms.
1995,
Pubmed
Campbell,
The calcium-independent transient outward potassium current in isolated ferret right ventricular myocytes. I. Basic characterization and kinetic analysis.
1993,
Pubmed
Campbell,
Ionic current mechanisms generating vertebrate primary cardiac pacemaker activity at the single cell level: an integrative view.
1992,
Pubmed
Carmeliet,
Use-dependent block and use-dependent unblock of the delayed rectifier K+ current by almokalant in rabbit ventricular myocytes.
1993,
Pubmed
Carmeliet,
Voltage- and time-dependent block of the delayed K+ current in cardiac myocytes by dofetilide.
1992,
Pubmed
Castellino,
Time- and voltage-dependent modulation of a Kv1.4 channel by a beta-subunit (Kv beta 3) cloned from ferret ventricle.
1995,
Pubmed
,
Xenbase
Clay,
A quantitative description of the E-4031-sensitive repolarization current in rabbit ventricular myocytes.
1995,
Pubmed
COLE,
Potassium ion current in the squid giant axon: dynamic characteristic.
1960,
Pubmed
Comer,
Cloning and characterization of an Ito-like potassium channel from ferret ventricle.
1994,
Pubmed
,
Xenbase
Curran,
A molecular basis for cardiac arrhythmia: HERG mutations cause long QT syndrome.
1995,
Pubmed
De Biasi,
Inactivation determined by a single site in K+ pores.
1993,
Pubmed
DiFrancesco,
The cardiac hyperpolarizing-activated current, if. Origins and developments.
1985,
Pubmed
Ho,
Voltage- and time-dependent block of delayed rectifier K+ current in rabbit sino-atrial node cells by external Ca2+ and Mg2+.
1996,
Pubmed
HODGKIN,
A quantitative description of membrane current and its application to conduction and excitation in nerve.
1952,
Pubmed
Hoshi,
Shaker potassium channel gating. I: Transitions near the open state.
1994,
Pubmed
,
Xenbase
Hoshi,
Biophysical and molecular mechanisms of Shaker potassium channel inactivation.
1990,
Pubmed
,
Xenbase
Jurkiewicz,
Rate-dependent prolongation of cardiac action potentials by a methanesulfonanilide class III antiarrhythmic agent. Specific block of rapidly activating delayed rectifier K+ current by dofetilide.
1993,
Pubmed
Liu,
Activation and inactivation kinetics of an E-4031-sensitive current from single ferret atrial myocytes.
1996,
Pubmed
López-Barneo,
Effects of external cations and mutations in the pore region on C-type inactivation of Shaker potassium channels.
1993,
Pubmed
,
Xenbase
McAllister,
Reconstruction of the electrical activity of cardiac Purkinje fibres.
1975,
Pubmed
Muraki,
Delayed rectifier K+ current in rabbit atrial myocytes.
1995,
Pubmed
Noble,
The surprising heart: a review of recent progress in cardiac electrophysiology.
1984,
Pubmed
Papazian,
Cloning of genomic and complementary DNA from Shaker, a putative potassium channel gene from Drosophila.
1987,
Pubmed
Rasmusson,
C-type inactivation controls recovery in a fast inactivating cardiac K+ channel (Kv1.4) expressed in Xenopus oocytes.
1995,
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
Shibasaki,
Conductance and kinetics of delayed rectifier potassium channels in nodal cells of the rabbit heart.
1987,
Pubmed
Shibata,
Ionic currents that generate the spontaneous diastolic depolarization in individual cardiac pacemaker cells.
1985,
Pubmed
Smith,
The inward rectification mechanism of the HERG cardiac potassium channel.
1996,
Pubmed
Spector,
Fast inactivation causes rectification of the IKr channel.
1996,
Pubmed
,
Xenbase
Taglialatela,
Novel voltage clamp to record small, fast currents from ion channels expressed in Xenopus oocytes.
1992,
Pubmed
,
Xenbase
Trudeau,
HERG sequence correction.
1996,
Pubmed
Trudeau,
HERG, a human inward rectifier in the voltage-gated potassium channel family.
1995,
Pubmed
Verheijck,
Effects of delayed rectifier current blockade by E-4031 on impulse generation in single sinoatrial nodal myocytes of the rabbit.
1995,
Pubmed
Wang,
Time, voltage and ionic concentration dependence of rectification of h-erg expressed in Xenopus oocytes.
1996,
Pubmed
,
Xenbase
Wang,
Rapid and slow components of delayed rectifier current in human atrial myocytes.
1994,
Pubmed
Wang,
Delayed rectifier outward current and repolarization in human atrial myocytes.
1993,
Pubmed
Warmke,
A family of potassium channel genes related to eag in Drosophila and mammals.
1994,
Pubmed
