| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Cardiology Division, Department of Internal Medicine, and Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan 48201
Although inactivation of the rapidly activating delayed rectifier current (IKr) limits outward current on depolarization, the role of IKr (and recovery from inactivation) during repolarization is uncertain. To characterize IKr during ventricular repolarization (and compare with the inward rectifier current, IK1), voltage-clamp waveforms simulating the action potential were applied to canine ventricular, atrial, and Purkinje myocytes. In ventricular myocytes, IKr was minimal at plateau potentials but transiently increased during repolarizing ramps. The IKr transient was unaffected by repolarization rate and maximal after 150-ms depolarizations (+25 mV). Action potential clamps revealed the IKr transient terminating the plateau. Although peak IKr transient density was relatively uniform among myocytes, potentials characterizing the peak transients were widely dispersed. In contrast, peak inward rectifier current (IK1) density during repolarization was dispersed, whereas potentials characterizing IK1 defined a narrower (more negative) voltage range. In summary, rapidly activating IKr provides a delayed voltage-dependent (and functionally time-independent) outward transient during ventricular repolarization, consistent with rapid recovery from inactivation. The heterogeneous voltage dependence of IKr provides a novel means for modulating the contribution of this current during repolarization.
arrhythmias; Purkinje fibers; human ether-à-go-go-related gene; atrial myocytes; canine myocardium
This article has been cited by other articles:
|
|
 |
|
  G. A. Gintant, Z. Su, R. L. Martin, and B. F. Cox Utility of hERG Assays as Surrogate Markers of Delayed Cardiac Repolarization and QT Safety Toxicol Pathol, January 1, 2006; 34(1): 81 - 90. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.M. Cordeiro, R. Brugada, Y.S. Wu, K. Hong, and R. Dumaine Modulation of IKr inactivation by mutation N588K in KCNH2: A link to arrhythmogenesis in short QT syndrome Cardiovasc Res, August 15, 2005; 67(3): 498 - 509. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Zhabyeyev, T. Asai, S. Missan, and T. F. McDonald Transient outward current carried by inwardly rectifying K+ channels in guinea pig ventricular myocytes dialyzed with low-K+ solution Am J Physiol Cell Physiol, November 1, 2004; 287(5): C1396 - C1403. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Hua and R. F. Gilmour Jr Contribution of IKr to Rate-Dependent Action Potential Dynamics in Canine Endocardium Circ. Res., April 2, 2004; 94(6): 810 - 819. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. H. W. J. ten Tusscher, D. Noble, P. J. Noble, and A. V. Panfilov A model for human ventricular tissue Am J Physiol Heart Circ Physiol, April 1, 2004; 286(4): H1573 - H1589. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Cabo and P. A. Boyden Electrical remodeling of the epicardial border zone in the canine infarcted heart: a computational analysis Am J Physiol Heart Circ Physiol, January 1, 2003; 284(1): H372 - H384. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Vornanen, A. Ryokkynen, and A. Nurmi Temperature-dependent expression of sarcolemmal K+ currents in rainbow trout atrial and ventricular myocytes Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2002; 282(4): R1191 - R1199. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Lu, M. P Mahaut-Smith, A. Varghese, C. L-H Huang, P. R Kemp, and J. I Vandenberg Effects of premature stimulation on HERG K+ channels J. Physiol., December 15, 2001; 537(3): 843 - 851. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Rocchetti, A. Besana, G. B Gurrola, L. D Possani, and A. Zaza Rate dependency of delayed rectifier currents during the guinea-pig ventricular action potential J. Physiol., August 1, 2001; 534(3): 721 - 732. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. A. Boyden Three Things You Should Know When Considering the Atria : Location, Location, Location Circ. Res., June 8, 2001; 88(11): 1097 - 1098. [Full Text] [PDF]
|
|
|
|
|
|
B.-R. Choi, T. Liu, and G. Salama The Distribution of Refractory Periods Influences the Dynamics of Ventricular Fibrillation Circ. Res., March 16, 2001; 88 (5): e49 - e58. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. Fox, J. L. McHarg, and R. F. Gilmour Jr Ionic mechanism of electrical alternans Am J Physiol Heart Circ Physiol, February 1, 2002; 282(2): H516 - H530. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
