Expression and functional role of small conductance Ca(2+)-activated K(+) channels in human atrial myocytes / 南方医科大学学报
Journal of Southern Medical University
; (12): 490-494, 2011.
Article
in Chinese
| WPRIM (Western Pacific)
| ID: wpr-307903
Responsible library:
WPRO
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the expression and functional role of the small conductance Ca(2+)-activated K(+) channels in human atrial myocytes.</p><p><b>METHODS</b>We collected the right atrial appendage tissues from 8 patients with congenital heart defect with sinus rhythm undergoing open-heart surgery. Immunohistochemistry was performed to identify the expression of 3 isoforms of SK channel (SK1, SK2 and SK3). Using the classical two-step enzymatic isolation method, perforated patch clamp and conventional voltage-clamp techniques were performed to record the action potentials (APs) and the whole-cell Ca(2+)-activated K(+) current (I(K, Ca)) in the single atrial myocyte. We compared the changes in action potential duration (APD) before and after the application of a specific SK channels blocker apamin (100 nmol/L).</p><p><b>RESULTS</b>Human atrial myocytes showed positivity for all the SK1, SK2 and SK3 isoform channels. Patch-clamp recording confirmed the presence of I(K,Ca), and apamin significantly prolonged APD at 90% repolarization (APD(90)), but produced no obvious effect on APD(50).</p><p><b>CONCLUSION</b>The three isoforms of SK channels are all expressed in human atrial myocytes. SK channels play a prominent role in the late phase of repolarization in human atrial myocytes, which is distinct from their functional roles in neurons where they mediate the process of afterhyperpolarization following APs.</p>
Full text:
Available
Database:
WPRIM (Western Pacific)
Main subject:
Physiology
/
Action Potentials
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Cells, Cultured
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Patch-Clamp Techniques
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Protein Isoforms
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Atrial Appendage
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Cell Biology
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Myocytes, Cardiac
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Small-Conductance Calcium-Activated Potassium Channels
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Metabolism
Limits:
Adolescent
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Female
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Humans
/
Male
Language:
Chinese
Journal:
Journal of Southern Medical University
Year:
2011
Document type:
Article