Freshly isolated bovine coronary endothelial cells do not express the BKCa channel gene

Kathryn M. Gauthier, Caiqiong Liu, Aleksandra Popovic, Sulayma Albarwani, Nancy J. Rusch

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Recent reports have suggested that different types of Ca2+-activated K+ channels may be selectively expressed either in the vascular endothelial cells (ECs) or smooth muscle cells (SMCs) of a single artery. In this study, we directly compared mRNA, protein and functional expression of the high-conductance Ca2+-activated K+ (BKCa) channel between freshly isolated ECs and SMCs from bovine coronary arteries. Fresh ECs and SMCs were enzymatically isolated, and their separation verified by immunofluorescent detection of α-actin and platelet/endothelium cell adhesion molecule (PECAM) proteins, respectively. Subsequently, studies using a sequence-specific antibody directed against the pore-forming α-subunit of the BKCa channel only detected its expression in the SMCs, whereas PECAM-positive ECs were devoid of the α-subunit protein. Additionally, multicell RTPCR performed using cDNA derived from either SMCs or ECs only detected mRNA encoding the BKCa α-subunit in the SMCs. Finally, whole-cell recordings of outward K+ current detected a prominent iberiotoxin-sensitive BKCa current in SMCs that was absent in ECs, and the BKCa channel opener NS 1619 only enhanced K+ current in the SMCs. Thus, bovine coronary SMCs densely express BKCa channels whereas adjacent ECs in the same artery appear to lack the expression of the BKCa channel gene. These findings indicate a cell-specific distribution of Ca2+-activated K+ channels in SMCs and ECs from a single arterial site.

Original languageEnglish
Pages (from-to)829-836
Number of pages8
JournalJournal of Physiology
Volume545
Issue number3
DOIs
Publication statusPublished - Dec 15 2002

ASJC Scopus subject areas

  • Physiology

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