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Swelling activated chloride currents in the electrical activity of pulmonary vein cardiomyocytes
Author(s) -
Lee S. H.,
Chen Y. C.,
Chen S. Y.,
Lin C. I.,
Chen Y. J.,
Chen S. A.
Publication year - 2008
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.2007.01898.x
Subject(s) - tonicity , electrophysiology , swell , atrial action potential , biophysics , patch clamp , atrial myocytes , medicine , myocyte , swelling , atrial fibrillation , pulmonary vein , chemistry , anatomy , biology , repolarization , pathology , oceanography , geology
Background Pulmonary veins (PVs) contain cardiomyocytes with a high arrhythmogenicity for inducing atrial fibrillation. The swelling‐activated outwardly rectifying Cl − currents (I Cl,swell ) are important in the electrical activity of cardiomyocytes. This study was to investigate whether I Cl,swell play a role in the PV electrophysiological characteristics. Materials and methods A whole‐cell patch clamp was used to investigate the action potentials and I Cl,swell in isolated rabbit single PV and atrial cardiomyocytes during immersion in isotonic (290–300 mosm L −1 ) and hypotonic (220–230 mosm L −1 ) solutions. The cell length and cell width were measured using confocal microscopy. Results Hypotonic solution induced larger I Cl,swell in the PV cardiomyocytes with pacemaker activity than those in the PV cardiomyocytes without pacemaker activity or atrial cardiomyocytes. Hypotonic solution shortened the action potential duration and increased the cell width to a greater extent in the PV cardiomyocytes than in the atrial cardiomyocytes. Moreover, hypotonic solution decreased the PV firing with a decrease in the transient inward currents and delayed after depolarizations. Conclusions These findings suggest that the I Cl,swell plays an important role in the electrical activity of the PV cardiomyocytes.