Ryanodine Receptor-Mediated Ca ²⁺ Events in Atrial Myocytes of Patients with Atrial Fibrillation

Abstract

Background: Many alterations in sarcoplasmic reticulum Ca²⁺ handling proteins in atrial myocytes have been associated with atrial fibrillation (AF) in clinical patients, whereas the functional consequences of these alterations mostly remain unclear. Methods and Results: To know whether or not ryanodine receptor (RyR)-mediated intracellular Ca²⁺ events in AF atrial myocytes are affected by protein alterations, we investigated spontaneous Ca²⁺ sparks and Ca²⁺ waves in intact and permeabilized atrial myocytes of AF patients (n_patients = 21) and normal sinus rhythm (NSR) patients (n_patients = 22) by laser scanning confocal microscopy. It was found that the frequency, amplitude and rise time of Ca²⁺ sparks were comparable between AF and NSR groups, while full width and full duration at half maximum intensity significantly increased in the AF group. Along with these changes, the frequency of small and global Ca²⁺ waves increased in AF atrial myocytes. Conclusions: Our results clearly indicated that the spatiotemporal properties but not the frequency of Ca²⁺ sparks were affected in AF atrial myocytes. In addition, the frequency of Ca²⁺ waves increased. This profile of the alterations in RyR-mediated Ca²⁺ events in AF atrial myocytes was different from previous studies. The underlying mechanisms, as well as possible reasons for this discrepancy, were discussed.

Journal

Journal ID (publisher-id): CRD

Journal ID (nlm-ta): Cardiology

Journal ID (doi): 10.1159/issn.0008-6312

Title: Cardiology

Publisher: S. Karger AG

ISSN (Print): 0008-6312

ISSN (Electronic): 1421-9751

Publication date Subscription-year: 2008

Publication date (Print): August 2008

Publication date (Electronic): 31 March 2008

Volume: 111

Issue: 2

Pages: 102-110

Affiliations

^aBio-X Life Science Research Center, College of Life Science and Biotechnology, Shanghai Jiao Tong University, ^bUnit of Cell Signal Transduction, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, ^cDepartment of Cardiac Surgery and Shanghai Institute of Cardiovascular Disease, Zhong Shan Hospital, Fu Dan University, and ^dShanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China

Article

Publisher ID: 119697 Other ID: Cardiology 2008;111:102–110

DOI: 10.1159/000119697

PubMed ID: 18376121

Copyright statement: © 2008 S. Karger AG, Basel

License:

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Page count

Figures: 4, Tables: 1, References: 25, Pages: 9

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Categories

Subject: Original Research