|
|
||||||||
1 Departments of Pharmacology and 2 Medicine and 3 Center for Molecular Therapeutics, Columbia University, College of Physicians and Surgeons, New York, New York 10032
We expressed human
delayed rectifier K+ cardiac current
(IKs) channels in the murine heart, which lacks
native IKs, to determine their
electrophysiological role. Mice expressing human
IKs channels were anesthetized, and an
electrocardiogram and monophasic action potentials (MAP) recorded from
the left ventricle. Sinus rate was not different between wild-type mice
(WT) and transgenic mice (TG). Infusion of isoproterenol accelerated WT
heart rate but not TG. Lack of TG sinus rate responsiveness may have
resulted from accumulated outward current in IKs
channels in sinus node. Ventricular MAP duration of TG mice to 50%
repolarization (APD50) during ventricular pacing was
shorter than WT, likely resulting from outward current through
IKs channels. TG APD50 showed
enhanced responsiveness (shortening) to isoproterenol compared with WT. Ventricular tachyarrhythmias were initiated in TG mice by programmed stimulation but not in WT and were accelerated by isoproterenol. IKs channels impart
-adrenergic sensitivity
to the ventricles and may be responsible for ventricular tachyarrhythmias.
arrhythmia;
-adrenergic; repolarization; heart rate; delayed
rectifier K+ cardiac current
This article has been cited by other articles:
![]() |
K. J. Sampson, C. Terrenoire, D. O. Cervantes, R. A. Kaba, N. S. Peters, and R. S. Kass Adrenergic regulation of a key cardiac potassium channel can contribute to atrial fibrillation: evidence from an IKs transgenic mouse J. Physiol., January 15, 2008; 586(2): 627 - 637. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Brisinda, M. E. Caristo, and R. Fenici Contactless magnetocardiographic mapping in anesthetized Wistar rats: evidence of age-related changes of cardiac electrical activity Am J Physiol Heart Circ Physiol, July 1, 2006; 291(1): H368 - H378. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Terrenoire, C. E. Clancy, J. W. Cormier, K. J. Sampson, and R. S. Kass Autonomic Control of Cardiac Action Potentials: Role of Potassium Channel Kinetics in Response to Sympathetic Stimulation Circ. Res., March 18, 2005; 96(5): e25 - e34. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. E. Bondarenko, G. P. Szigeti, G. C. L. Bett, S.-J. Kim, and R. L. Rasmusson Computer model of action potential of mouse ventricular myocytes Am J Physiol Heart Circ Physiol, September 1, 2004; 287(3): H1378 - H1403. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Tosaka, M. C. Casimiro, Q. Rong, S. Tella, M. Oh, A. N. Katchman, J. C. Pezzullo, K. Pfeifer, and S. N. Ebert Nicotine Induces a Long QT Phenotype in Kcnq1-Deficient Mouse Hearts J. Pharmacol. Exp. Ther., September 1, 2003; 306(3): 980 - 987. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |