Referenced in: none

Automatically associated channels: SK1 , SK2 , SK3

Title: [Expression and functional role of small conductance Ca(2+)-activated K(+) channels in human atrial myocytes].

Authors: Tao Yu, Ruo-bin WU, Hui-ming GUO, Chun-yu Deng, Shao-yi ZHENG, Su-Juan Kuang

Journal, date & volume: Nan Fang Yi Ke Da Xue Xue Bao, 2011 Mar , 31, 490-4

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/21421490

Abstract
To investigate the expression and functional role of the small conductance Ca(2+)-activated K(+) channels in human atrial myocytes.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).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).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.