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D5 receptor mediates Dopamine effects on Big K<Ca> channels in human coronary artery smooth muscle cells
Author(s) -
Natarajan Aruna,
Han Guichun,
White Richard,
Jose Pedro
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a301-d
Subject(s) - dopamine , medicine , smooth muscle , chemistry , cardiology , artery , endocrinology , biophysics , microbiology and biotechnology , biology
We sought to identify the D1‐like receptor (D1R or D5R) involved in dopamine‐stimulated activity of large‐conductance calcium‐ and voltage‐activated potassium (BK Ca ) channels in human coronary artery smooth muscle cells (HCASMC). HCASMC, purchased from Cambrex, were grown to passage 5–6.D1 and D5 dopamine receptor mRNA expression was demonstrated by RT‐PCR. Probability of opening of BK Ca channel (NPo), studied by single cell patch‐clamp, was 0.0083. It increased to 0.0982, with 1μM Fenoldopam (2 min), a D1‐like receptor partial agonist. 10 μM SCH 23390, a D1‐like receptor antagonist, reduced BK Ca channel activity (NPo = 0.0512, 2 min). HCASMC were transfected with antisense (AS) and scrambled (Scr) oligonucleotides for D1 and D5 receptors. Cells transfected with D1 AS and Scr oligonucleotides, and D5 Scr oligonucleotides showed similar BK Ca channel response as controls. Transfection with D5 AS oligonucleotides abolished BK Ca channel response to fenoldopam 10μM (20 min), and SKF 12987 (a full agonist of D1‐like receptors) 1μM (10 min) and 10μM (20 min). Thus, D5, but not D1, receptors mediate D1‐like receptor agonist‐stimulation of BK Ca channels in HCASMC, implicated in human coronary vasorelaxation. Grants RR 17613, NCRR, NIH (A.N. and P.J.), American Heart Association (G.H.) and NHLBI (HL073890, R.W), supported this work.