An ionic model of stretch-activated and stretch-modulated currents in rabbit ventricular myocytes

Healy, Sarah N. and McCulloch, Andrew D. (2005). An ionic model of stretch-activated and stretch-modulated currents in rabbit ventricular myocytes. In: A. John Camm, Europace. Proceedings of the Fourth International Workshop on Computer Simulation and Experimental Assessment of Cardiac Electrical Function. 4th International Workshop on Computer Simulation and Experimental Assessment of Cardiac Electrical Function, Cap d Ail, France, (128-134). 14-15 June 2004. doi:10.1016/j.eupc.2005.03.019


Author Healy, Sarah N.
McCulloch, Andrew D.
Title of paper An ionic model of stretch-activated and stretch-modulated currents in rabbit ventricular myocytes
Conference name 4th International Workshop on Computer Simulation and Experimental Assessment of Cardiac Electrical Function
Conference location Cap d Ail, France
Conference dates 14-15 June 2004
Proceedings title Europace. Proceedings of the Fourth International Workshop on Computer Simulation and Experimental Assessment of Cardiac Electrical Function   Check publisher's open access policy
Journal name Europace   Check publisher's open access policy
Place of Publication London,U.K. ; Philadelphia, PA, U.S.A.
Publication Year 2005
Sub-type Fully published paper
DOI 10.1016/j.eupc.2005.03.019
ISSN 1099-5129
1532-2092
Editor A. John Camm
Volume 7
Issue Suppl. 2
Start page 128
End page 134
Total pages 7
Language eng
Formatted Abstract/Summary
Aims: To develop an ionic model of stretch-activated and stretch-modulated currents in rabbit ventricular myocytes consistent with experimental observations, that can be used to investigate the role of these currents in intact myocardium.
Methods and results: A non-specific cation-selective stretch-activated current Ins, was incorporated into the Puglisi-Bers ionic model of epicardial, endocardial and midmyocardial ventricular myocytes. Using the model, we predict a reduction in action potential duration at 20% repolarization (APD20) and action potential amplitude, an elevated resting transmembrane potential and either an increase or decrease in APD90, depending on the reversal potential of Ins. A stretch-induced decrease in IK1 (70%), plus a small Ins current (gns=10 pS), results in a reduction in APD20 and increase in APD90, and a reduced safety factor for conduction. Increasing IK1 (150%) plus a large Ins current (gns=40 pS), also leads to a reduction in APD20 and increase in APD90, but with a greater safety factor. Endocardial and midmyocardial cells appear to be the most sensitive to stretch-induced changes in action potential. The addition of the K+-specific stretch-activated current (SAC) IKo results in action potential shortening.
Conclusion: Transmural heterogeneity of IKo may reduce repolarization gradients in intact myocardium caused by intrinsic ion channel densities, nonuniform strains and electrotonic effects.
© 2005 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.
Subjects 1103 Clinical Sciences
Keyword Stretch-activated channels
Transmural heterogeneity
Rabbit cardiomyocyte
Q-Index Code EX

 
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Created: Tue, 13 Apr 2010, 09:17:15 EST by June Temby on behalf of Faculty Of Health Sciences