Rectifier potassium current

Ikr is a rapidly activating component of the delayed rectifier potassium current. Ikr stands for potassium (K) rectifier (r) cuirent (I). Ikr is characterized by delayed... 

As with the effects of oxidant stress on the calcium channel, part of the change in the steady-state background current could also be attributed to an indirect effect secondary to the elevation of intracellular calcium (Matsuura and Shattock, 1991b). However, oxidant stress also exerted a direct effect on the inward rectifying potassium current (7ki). The combination of an inhibition of 7ki and the activation of a calcium-dependent current are likely to contribute to the prolongation of the action potential duration and the increased susceptibility... 

Bertran, G.C. and B.A. Kotsias. 1997. Blockade of the inward rectifier potassium currents by zinc and nickel ions in voltage-clamped toad muscles. Life Sci. 60 119-125. 

Liu XK, Katchman A, Ebert SN, Woosley RL (1998) The antiestrogen tamoxifen blocks the delayed rectifier potassium current, IKr, in rabbit ventricular myocytes. J Pharmacol Exp Ther 287 877-883... 

Mitcheson, J.S. and Hancox, J.C. (1999) An investigation of the role played by the E-4031 sensitive (rapid delayed rectifier) potassium current in isolated rabbit atrioventricular nodal and ventricular myocytes. Pflugers Archiv European Journal of Physiology, 438, 843-850. 

A benzopyran derivative, RP-58866 (70) is under development by Rhone-Poulenc. Patch clamp studies in guinea-pig ventricular myocytes indicate that RP-58866 inhibits the inward rectifying potassium current (7ki) with no effects on the delayed rectifier, ATP-sensitive potassium currents or calcium currents [200]. RP-58866 increases APD90 of Purkinje fibres by about 45% at 0.3 yuM without affecting K ax [201]. The compound was effective... 

Fast Inward Sodium Current L Type Calcium Current Transient Outward Current Sodium-Calcium Exchange Current ATP Sensitive Potassium Current Inward Rectifying Potassium Current Delayed Rectifying Potassium Current... 

The actions of sotalol on the delayed rectifier potassium current prolong the ERP in His-Purkinje tissue. As with other members of class III, the electrophysiological action of sotalol is characterized by prolongation of repolarization and an increase in the ERP of ventricular muscle. 

Dofetilide (Tikosyn) is a pure class III drug. It prolongs the cardiac action potential and the refractory period by selectively inhibiting the rapid component of the delayed rectifier potassium current (IKr). 

Dofetilide s mechanism of action involves blockade of the cardiac ion channel that carries the rapid component of the delayed rectifier potassium current, IKr. Dofetilide inhibits IKr with no significant effects on other repolarizing potassium currents (e.g., IKs, IKl) over a wide range of concentrations. At plasma concentrations within the therapeutic range, dofetilide has no effect on sodium channels or on either i- or p-adreno-ceptors. 

It blocks inactivated sodium channels. It also decreases calcium current and transient outward, delayed rectifier and inward rectifier potassium currents. It is a potent inhibitor of abnormal automaticity. It prolongs duration of action potential, refracto-... 

Dofetilide has class 3 action potential prolonging action. This action is effected by a dose-dependent blockade of the rapid component of the delayed rectifier potassium current, IKr, and the blockade of IKr increases in hypokalemia. Dofetilide produces no relevant blockade of the other potassium channels or the sodium channel. Because of the slow rate of recovery from blockade, the extent of blockade shows little dependence on stimulation frequency. However, dofetilide does show less action potential prolongation at rapid rates because of the increased importance of other potassium channels such as IKs at higher frequencies. 

Pogwizd, S.M., Schlotthauer, K., Li, L., et al., 2001, Arrhythmogenesis and contractile dysfunction in heart failure Roles of sodium-calcium exchange, inward rectifier potassium current, and residual beta-adrenergic responsiveness. Circ Res., 88(11), pp 1159—67. 

QT interval prolongation induced by phenothiazines suggests that potassium channels responsible for the repolarization phase of myocardial action potential are naturally the first candidates for the possible interaction with these drugs. Wooltorton and Mathie [244] using a whole-cell voltage clamp found that in isolated rat sympathetic neurons, CPZ (9) inhibited mostly delayed rectified potassium current, leaving the transient K+ current almost... 

Class III antiarrhythmic drug, which prolongs repolarization by inhibition of the delayed rectifier potassium current (lkr) and by selective enhancement of the slow inward sodium current, Ibutilide has no known negative inotropic effects (53),... 

This review focuses on the recent discovery and development of chemical entities targeting the Kvl.5 potassium channel subunit for the treatment of atrial arrhythmias. This strategy is based on the expression of the ultrarapidly activating delayed rectifier potassium current, /Run in atria but not ventricles of humans, and on the molecular characterization of the Kvl.5 channel subunit as a structural correlate of JRur [1-6]. Although no perfectly selective Kvl.5... 

Purpose What is the potential of the test article to prolong the human QT interval in vivo by assessing the rapidly inward rectifying potassium current (Kr) conducted by hERG (human ether-a-go-go related gene) channels stably expressed in a HEK293 cell line ... 

Biopharmaceuticals or pharmaceuticals dissolved in Tyrodes s solution to obtain at least 5 different concentrations Biopharmaceuticals and pharmaceuticals formulated by the CRO and require formulation analysis for concentration, homogeneity, and stability dl-soltalol, a P-adrenergic antagonist that prolongs cardiac action potential by selectively blocking the rapidly activating delayed rectifier potassium current (IKr)... 

---