Skip Navigation

Cardiovascular Research 1998 40(2):322-331; doi:10.1016/S0008-6363(98)00133-3
© 1998 by European Society of Cardiology
This Article
Right arrow Full Text Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow E-letters: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when E-letters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
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 Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Bryant, S. M.
Right arrow Articles by Hart, G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bryant, S. M.
Right arrow Articles by Hart, G.
Social Bookmarking
 Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Copyright © 1998, European Society of Cardiology

Regional differences in the delayed rectifier current (IKr and IKs) contribute to the differences in action potential duration in basal left ventricular myocytes in guinea-pig

Simon M. Bryanta,*, Xiaoping Wana, S.Jane Shipseyb and George Harta

aDepartment of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
bDepartment of Cardiology, The London Chest Hospital, Bonner Road, London, UK

* Corresponding author. Tel.: +44 (1865) 22 01 33; Fax: +44 (1865) 22 19 77.

Objective: To compare the properties of single myocytes isolated from different layers of the basal region of the left ventricle and to test the hypothesis that differences in the delayed rectifier current (IK) contribute to regional differences in action potential duration. Methods: Myocytes were isolated from basal sub-endocardial, mid-myocardial and sub-epicardial layers of the guinea-pig left ventricle. Membrane voltage and current were measured using the switch-clamp technique. Results: Mean action potential duration measured at 90% repolarisation (APD90) was longer in sub-endocardial myocytes than in mid-myocardial and sub-epicardial myocytes [APD90 ms at 0.2 Hz: sub-endocardial 292±12 (n=40), mid-myocardial 243±8 (n=42) and sub-epicardial 227±9 (n=36), P<0.001, analysis of variance (ANOVA)]. The APD–rate relationship (stimulation frequencies 2, 1, 0.2 and 0.017 Hz) was steeper in sub-endocardial than in mid-myocardial or sub-epicardial myocytes (P<0.001, ANOVA). The density of IK was greater in mid-myocardial (4.05±0.09 pA pF–1) and sub-epicardial (3.90±0.41 pA pF–1) than in sub-endocardial myocytes (2.74±0.27 pA pF–1, P<0.01 ANOVA). The rapidly-activating (IKr) and slowly-activating (IKs) components of IK were significantly smaller in sub-endocardial than in mid-myocardial or sub-epicardial myocytes. D,L-Sotalol-induced prolongation of APD90 was similar in the three regions studied. Conclusions: There are significant transmural gradients in the electrophysiological properties of myocytes isolated from the base of the left ventricular free wall in guinea-pig. Sub-endocardial myocytes had a longer APD90 attributable in part to a significantly smaller IK density. We have been unable to identify M cells in the guinea-pig left ventricular free wall.

KEYWORDS Heart; Electrophysiology; Action potential duration; Ventricular myocytes; Guinea-pig; Potassium current; Antiarrhythmic agents


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
Cardiovasc ResHome page
G. Michael, L. Xiao, X.-Y. Qi, D. Dobrev, and S. Nattel
Remodelling of cardiac repolarization: how homeostatic responses can lead to arrhythmogenesis
Cardiovasc Res, February 15, 2009; 81(3): 491 - 499.
[Abstract] [Full Text] [PDF]


Home page
Circ. Res.Home page
B. J.D. Boukens, V. M. Christoffels, R. Coronel, and A. F.M. Moorman
Developmental Basis for Electrophysiological Heterogeneity in the Ventricular and Outflow Tract Myocardium As a Substrate for Life-Threatening Ventricular Arrhythmias
Circ. Res., January 2, 2009; 104(1): 19 - 31.
[Abstract] [Full Text] [PDF]


Home page
J. Physiol.Home page
X. Sun and H.-S. Wang
Role of the transient outward current (Ito) in shaping canine ventricular action potential - a dynamic clamp study
J. Physiol., April 15, 2005; 564(2): 411 - 419.
[Abstract] [Full Text] [PDF]


Home page
J. Physiol.Home page
H.-S. Wang and I. S Cohen
Calcium channel heterogeneity in canine left ventricular myocytes
J. Physiol., March 15, 2003; 547(3): 825 - 833.
[Abstract] [Full Text] [PDF]


Home page
J. Physiol.Home page
M Lei, H Honjo, I Kodama, and M R Boyett
Heterogeneous expression of the delayed-rectifier K+ currents iK,r and iK,s in rabbit sinoatrial node cells
J. Physiol., September 15, 2001; 535(3): 703 - 714.
[Abstract] [Full Text] [PDF]


Home page
J. Physiol.Home page
J. M Nerbonne
Molecular basis of functional voltage-gated K+ channel diversity in the mammalian myocardium
J. Physiol., June 1, 2000; 525(2): 285 - 298.
[Abstract] [Full Text] [PDF]


Home page
J. Physiol.Home page
A. Varro, B. Balati, N. Iost, J. Takacs, L. Virag, D. A Lathrop, L. Csaba, L. Talosi, and J. G. Papp
The role of the delayed rectifier component IKs in dog ventricular muscle and Purkinje fibre repolarization
J. Physiol., February 15, 2000; 523(1): 67 - 81.
[Abstract] [Full Text] [PDF]



Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.