All issues > Volume 43(7); 2000

Original Article

J Korean Pediatr Soc. 2000;43(7):905-912. Published online July 15, 2000.

Identification of a Calcium-activated Potassium Channel Gene Expressed in Rat Cardiac Myocytes

In Seung IS Park¹, Hyun-Kyu HK Jeon², Nam Su NS Kim³, Youn Mo YM Ahn³, Chul-Seung CS Park², Ha Baik HB ³

¹Department of P ediatrics, Sejong General Hospital
²Department of Life Science, Kwangju
²Department of Life Science, Kwangju
³Department of P ediatrics, Hanyang University, Seoul
³Department of P ediatrics, Hanyang University, Seoul
³Department of P ediatrics, Hanyang University, Seoul

Abstract

Purpose
: Calcium-activated potassium channels(KCa) may be involved in the transient outward current of the first phase of cardiac action potential. But it is still not clear whether cardiac myocytes express any KCa. We try to identify here the types of KCa expressed in rat caridac myocytes.
Methods
: We isolated total heart RNA from 50 rats(Spague-Dawley) and performed reverse transcription-polymerase chain reaction(RT-PCR) using specifically designed synthetic oligonucleotide primer sets. From the pure culture of cardiac myocyte, KCa gene expression was detected by Southern blot analysis.
Results
: RT-PCR revealed expressions of BKCa(large-conductance KCa, rSlo) and SKCa(small-conductance KCa, rSK1). We prepared cardiac myocytes pure culture(> 95% pure myocyte) using pure culture technique. RT-PCR and Southern blot analysis of rat cardiac myocyte showed only rSK1-specific band, but no rSlo-specific was detected.
Conclusion
: The expressions of more than one type of KCa are detected from rat heart. A subtype of SKCa, rSK1, was expressed in cardiac myocyte, while the main subunit of BKCa(rSlo) was found in cells other than myocytes, most likely in the smooth muscle of cardiac blood vessels.

Keywords :Heart, Cardiac Myocyte, Calcium-activated potassium channel