HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 285/5/H1837    most recent 00386.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (14) Citing Articles via Google Scholar Google Scholar Articles by Lomax, A. E. Articles by Giles, W. R. Search for Related Content PubMed PubMed Citation Articles by Lomax, A. E. Articles by Giles, W. R.

Comparison of time- and voltage-dependent K⁺ currents in myocytes from left and right atria of adult mice

¹Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta T2N 4N1, Canada; and ²Department of Bioengineering, University of California, San Diego, La Jolla, California 92093-0412

Submitted 25 April 2003 ; accepted in final form 13 July 2003

Consistent differences in K⁺ currents in left and right atria of adult mouse hearts have been identified by the application of current- and voltage-clamp protocols to isolated single myocytes. Left atrial myocytes had a significantly (P < 0.05) larger peak outward K⁺ current density than myocytes from the right atrium. Detailed analysis revealed that this difference was due to the rapidly activating sustained K⁺ current, which is inhibited by 100 µM 4-aminopyridine (4-AP); this current was almost three times larger in the left atrium than in the right atrium. Accordingly, 100 µM 4-AP caused a significantly (P < 0.05) larger increase in action potential duration in left than in right atrial myocytes. Inward rectifier K⁺ current density was also significantly (P < 0.05) larger in left atrial myocytes. There was no difference in the voltage-dependent L-type Ca²⁺ current between left and right atria. As expected from this voltage-clamp data, the duration of action potentials recorded from single myocytes was significantly (P < 0.05) shorter in myocytes from left atria, and left atrial tissue was found to have a significantly (P < 0.05) shorter effective refractory period than right atrial tissue. These results reveal similarities between mice and other mammalian species where the left atrium repolarizes more quickly than the right, and provide new insight into cellular electrophysiological mechanisms responsible for this difference. These findings, and previous results, suggest that the atria of adult mice may be a suitable model for detailed studies of atrial electrophysiology and pharmacology under control conditions and in the context of induced atrial rhythm disturbances.

action potential; atrial repolarization; mouse heart

This article has been cited by other articles:

				M. E. Loewen, Z. Wang, J. Eldstrom, A. Dehghani Zadeh, A. Khurana, D. F. Steele, and D. Fedida Shared requirement for dynein function and intact microtubule cytoskeleton for normal surface expression of cardiac potassium channels Am J Physiol Heart Circ Physiol, January 1, 2009; 296(1): H71 - H83. [Abstract] [Full Text] [PDF]

				Y. Etzion, M. Mor, A. Shalev, S. Dror, O. Etzion, A. Dagan, O. Beharier, A. Moran, and A. Katz New insights into the atrial electrophysiology of rodents using a novel modality: the miniature-bipolar hook electrode Am J Physiol Heart Circ Physiol, October 1, 2008; 295(4): H1460 - H1469. [Abstract] [Full Text] [PDF]

				B. K. Panama, M. McLerie, and A. N. Lopatin Heterogeneity of IK1 in the mouse heart Am J Physiol Heart Circ Physiol, December 1, 2007; 293(6): H3558 - H3567. [Abstract] [Full Text] [PDF]

				B. C. Knollmann, T. Schober, A. O. Petersen, S. G. Sirenko, and M. R. Franz Action potential characterization in intact mouse heart: steady-state cycle length dependence and electrical restitution Am J Physiol Heart Circ Physiol, January 1, 2007; 292(1): H614 - H621. [Abstract] [Full Text] [PDF]

				Y. Shimoni, D. Hunt, K. Chen, T. Emmett, and G. Kargacin Differential autocrine modulation of atrial and ventricular potassium currents and of oxidative stress in diabetic rats Am J Physiol Heart Circ Physiol, May 1, 2006; 290(5): H1879 - H1888. [Abstract] [Full Text] [PDF]

				R. Ochi, Y. Momose, K. Oyama, and W. R. Giles Sphingosine-1-phosphate effects on guinea pig atrial myocytes: Alterations in action potentials and K+ currents Cardiovasc Res, April 1, 2006; 70(1): 88 - 96. [Abstract] [Full Text] [PDF]

				Y. Hu, S. V. P. Jones, and W. H. Dillmann Effects of hyperthyroidism on delayed rectifier K+ currents in left and right murine atria Am J Physiol Heart Circ Physiol, October 1, 2005; 289(4): H1448 - H1455. [Abstract] [Full Text] [PDF]

				J. Temple, P. Frias, J. Rottman, T. Yang, Y. Wu, E. E. Verheijck, W. Zhang, C. Siprachanh, H. Kanki, J. B. Atkinson, et al. Atrial Fibrillation in KCNE1-Null Mice Circ. Res., July 8, 2005; 97(1): 62 - 69. [Abstract] [Full Text] [PDF]

				A. Nygren, A. E. Lomax, and W. R. Giles Heterogeneity of action potential durations in isolated mouse left and right atria recorded using voltage-sensitive dye mapping Am J Physiol Heart Circ Physiol, December 1, 2004; 287(6): H2634 - H2643. [Abstract] [Full Text] [PDF]