help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Biophys. J. BioFAST: First Published July 14, 2006. doi:10.1529/biophysj.106.083865
© 2006 by the Biophysical Society.

A more recent version of this article appeared on October 1, 2006.
This Article
Right arrow Full Text (Rapid PDF)
Right arrow All Versions of this Article:
biophysj.106.083865v1
91/7/2735    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Tolkacheva, E. G.
Right arrow Articles by Jalife, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Tolkacheva, E. G.
Right arrow Articles by Jalife, J.

ELECTROPHYSIOLOGY

ACTION POTENTIAL DURATION RESTITUTION PORTRAITS OF MAMMALIAN VENTRICULAR MYOCYTES Role of calcium current

Elena G. Tolkacheva 1*, Justus M.B. Anumonwo 1 and Jose Jalife 1

1 SUNY Upstate Medical University

* To whom correspondence should be addressed. E-mail: talkacal{at}upstate.edu.

Submitted on February 23, 2006
Revised on April 2, 2006
Accepted on 22 June 2006


  Abstract
Construction of the action potential duration (APD) restitution portrait allows visualization of multiple aspects of the dynamics of periodically paced myocytes at various basic cycle lengths (BCLs). For the first time, we obtained the restitution portrait of isolated rabbit and guinea pig cardiac ventricular myocytes and analyzed the time constant, {tau}, of APD accommodation and the slopes of different types of restitution curves (RC), Sdyn and S12, measured at varying BCLs. Our results indicate that both {tau} and the individual slopes are species- and pacing-dependent. In contrast, the mutual relationship between slopes Sdyn and S12 does not depend on pacing history, being a generic feature of the species. In addition, the maximum slope S12, measured in the restitution portrait at the lowest BCL, predicts the onset of alternans. Further, we investigated the role of the L-type calcium current, ICa-L, in the restitution portrait. We found that ICa-L dramatically affects APD accommodation, as well as the individual slopes Sdyn and S12 measured in the restitution portrait. However, peak calcium current plays a role only at small values of BCL. In conclusion, the results demonstrate that the restitution portrait is a powerful technique to investigate restitution properties of periodically paced cardiac myocytes, and the onset of alternans, in particular. Moreover, the data also show that ICa-L plays a crucial role in multiple aspects of cardiac dynamics measured through the restitution portrait.

Key Words: APD accommodation, action potential duration, alternans, calcium current, cardiac myocytes, restitution curve




This article has been cited by other articles:


Home page
 Biophys. JHome page
A. Munteanu, A. A. Kondratyev, and J. P. Kucera
Analysis of Damped Oscillations during Reentry: A New Approach to Evaluate Cardiac Restitution
Biophys. J., February 1, 2008; 94(3): 1094 - 1109.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2006 by the Biophysical Society.