Faculty Collaboration Database

Freshly isolated bovine coronary endothelial cells do not express the BK Ca channel gene. J Physiol 2002 Dec 15;545(3):829-36

Date

12/17/2002

Pubmed ID

12482889

Pubmed Central ID

PMC2290710

DOI

10.1113/jphysiol.2002.029843

Scopus ID

2-s2.0-0037115190 (requires institutional sign-in at Scopus site)   59 Citations

Abstract

Recent reports have suggested that different types of Ca(2+)-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 Ca(2+)-activated K(+) (BK(Ca)) 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 alpha-actin and platelet/endothelium cell adhesion molecule (PECAM) proteins, respectively. Subsequently, studies using a sequence-specific antibody directed against the pore-forming alpha-subunit of the BK(Ca) channel only detected its expression in the SMCs, whereas PECAM-positive ECs were devoid of the alpha-subunit protein. Additionally, multicell RT-PCR performed using cDNA derived from either SMCs or ECs only detected mRNA encoding the BK(Ca) alpha-subunit in the SMCs. Finally, whole-cell recordings of outward K(+) current detected a prominent iberiotoxin-sensitive BK(Ca) current in SMCs that was absent in ECs, and the BK(Ca) channel opener NS 1619 only enhanced K(+) current in the SMCs. Thus, bovine coronary SMCs densely express BK(Ca) channels whereas adjacent ECs in the same artery appear to lack the expression of the BK(Ca) channel gene. These findings indicate a cell-specific distribution of Ca(2+)-activated K(+) channels in SMCs and ECs from a single arterial site.

Author List

Gauthier KM, Liu C, Popovic A, Albarwani S, Rusch NJ

MESH terms used to index this publication - Major topics in bold

Animals
Cattle
Coronary Vessels
Endothelium, Vascular
Gene Expression
In Vitro Techniques
Large-Conductance Calcium-Activated Potassium Channel alpha Subunits
Large-Conductance Calcium-Activated Potassium Channels
Muscle, Smooth, Vascular
Myocytes, Smooth Muscle
Patch-Clamp Techniques
Potassium Channels, Calcium-Activated
RNA, Messenger