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

• Published in: Nan fang yi ke da xue xue bao = Journal of Southern Medical University Vol. 31; no. 3; p. 490
• Main Authors: YU, Tao, WU, Ruo-bin, GUO, Hui-ming, DENG, Chun-yu, ZHENG, Shao-yi, KUANG, Su-juan
• Format: Journal Article
• Language: Chinese
• Published: China 01.03.2011
• Subjects: Action Potentials - physiology; Adolescent; Atrial Appendage - cytology; Cells, Cultured; Female; Humans; Male; Myocytes, Cardiac - metabolism; Patch-Clamp Techniques; Protein Isoforms - metabolism; Protein Isoforms - physiology; Small-Conductance Calcium-Activated Potassium Channels - metabolism; Small-Conductance Calcium-Activated Potassium Channels - physiology
• ISSN: 1673-4254

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