Expression and functional role of small conductance Ca(2+)-activated K(+) channels in human atrial myocytes.
- Author:
Tao YU
1
;
Ruo-bin WU
;
Hui-ming GUO
;
Chun-yu DENG
;
Shao-yi ZHENG
;
Su-juan KUANG
Author Information
- Publication Type:Journal Article
- MeSH: Action Potentials; physiology; Adolescent; Atrial Appendage; cytology; Cells, Cultured; Female; Humans; Male; Myocytes, Cardiac; metabolism; Patch-Clamp Techniques; Protein Isoforms; metabolism; physiology; Small-Conductance Calcium-Activated Potassium Channels; metabolism; physiology
- From: Journal of Southern Medical University 2011;31(3):490-494
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVETo investigate the expression and functional role of the small conductance Ca(2+)-activated K(+) channels in human atrial myocytes.
METHODSWe 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).
RESULTSHuman 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).
CONCLUSIONThe 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.