Skip Navigation


Cardiovascular Research Advance Access originally published online on September 18, 2008
Cardiovascular Research 2009 81(1):82-89; doi:10.1093/cvr/cvn255
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
81/1/82    most recent
cvn255v2
cvn255v1
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 Barajas-Martinez, H.
Right arrow Articles by Dumaine, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Barajas-Martinez, H.
Right arrow Articles by Dumaine, R.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2008. For permissions please email: journals.permissions@oxfordjournals.org

Larger dispersion of INa in female dog ventricle as a mechanism for gender-specific incidence of cardiac arrhythmias

Hector Barajas-Martinez1,{dagger}, Volker Haufe1,{dagger}, Caroline Chamberland1, Marie-Josée Blais Roy1, Marie Hélène Fecteau1, Jonathan M. Cordeiro2 and Robert Dumaine1,*

1 Department of Physiology and Biophysics, Faculty of Medicine, University of Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, Quebec, Canada J1H 5N4
2 Masonic Medical Research Laboratory, Utica, NY, USA

* Corresponding author. Tel: +1 819 820 6868, ext 12556; +1 819 820 6887. E-mail address: robert.dumaine{at}usherbrooke.ca

Aims: Women have a higher incidence of long QT-related arrhythmias, whereas men exhibit a higher incidence of Brugada syndrome (BrS). The cardiac sodium current (INa) is associated with arrhythmias in BrS and long QT-syndrome (LQTS) and conduction disease. Although a great deal of work has been performed to explain how heterogeneous distribution of repolarizing currents triggers arrhythmias, the transmural distribution of INa within the cardiac ventricle and its contribution to generate the arrhythmogenic substrate remain unknown. We undertook to determine whether INa was heterogeneously distributed within the ventricular wall of canine heart, an animal model close to humans.

Methods and results: Using patch-clamp and molecular biology techniques, we tested whether gender differences exist in the ventricular distribution and amplitude of INa in the canine heart model. Our results show that the INa amplitude is smaller in the female epicardial and endocardial layers of the left ventricle, but similar to male in the mid-myocardium. Exposure of female cardiomyocytes to testosterone increased the amplitude of INa to levels similar to male in epicardium, but had no effects in mid-myocardial and endocardial cells. Castrated male dogs displayed INa amplitudes similar to what was found in female hearts.

Conclusion: The larger dispersion of INa amplitude within the female cardiac ventricle may contribute to the higher risk of arrhythmias in females. Testosterone modulates this dispersion. By decreasing the transmural dispersion of INa, testosterone may exert a protective effect against LQTS-related arrhythmias in males.

KEYWORDS Sodium current; Female; Male; Testosterone

Time for primary review: 23 days

{dagger} These authors contributed equally to this work.


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




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.