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Characterization of Ca 2+ ‐activated K + current in human cardiac fibroblasts: its contribution to electrical coupling of cardiomyocyte‐fibroblast
Author(s) -
Wang YaJean,
Wu ShengNan,
Lin MingWei,
Sung Ruey J
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a957
Subject(s) - gap junction , fibroblast , coupling (piping) , iberiotoxin , myocyte , depolarization , cardiac action potential , biophysics , intracellular , chemistry , microbiology and biotechnology , electrophysiology , medicine , repolarization , biology , materials science , potassium channel , in vitro , biochemistry , metallurgy
Cardiac fibroblasts can maintain myocardial tissue structure. Cardiac fibroblasts can interact electrically with cardiomyocytes through gap junctions. Little was reported about ion currents in human cardiac fibroblasts. Ca 2+ ‐activated K + currents ( I K(Ca) ) of cultured human cardiac fibroblasts were characterized in this study. In whole‐cell configuration, depolarizing pulses evoked I K(Ca) in these cells, the amplitude of which was suppressed by paxilline (1 μM) or iberiotoxin (200 nM). Western blot analysis revealed the presence of α‐subunit of BK Ca channels. Dynamic Luo‐Rudy model was applied to predict cell behavior during direct electrical coupling of cardiomyocyte and cardiac fibroblast. In the simulation, electrically coupled cardiac fibroblast was found to exhibit action potential. The simulation predicts that gap junction coupling conductance influences cardiac action potential and excitability. I K(Ca) can be elicited by simulated action potential waveforms of cardiac fibroblasts when they are electrically coupled to cardiomyocytes. This study demonstrates that a BK Ca channel is functionally expressed in human cardiac fibroblasts. The BK Ca ‐channel activity in human cardiac fibroblast may contribute to the functional activities of heart cells through transfer of electrical signals between these two cells.