Heterogeneous Kv1 Function and Expression in Coronary Myocytes from Right and Left Ventricles in Rats.
From: LABPART-EA 3852, UFR Médecine, Université François Rabelais, 10 Bld Tonnellé-BP 3223, 37032 Tours Cedex-France.
American journal of physiology. Heart and circulatory physiology
- Publish Date: Jan 2007
- ISSN: 0363-6135
- Volume: 292
- Issue: 1
- Pages: H475-82
- Medium: Print
- Language: English
- Citation (JAMA): Gautier Mathieu, Hyvelin Jean-Marc, de Crescenzo Valérie, et al. Heterogeneous Kv1 Function and Expression in Coronary Myocytes from Right and Left Ventricles in Rats.. Am. J. Physiol. Heart Circ. Physiol. Jan 2007;292:H475-82
Abstract
Coronary blood flow control is not uniform along the vascular tree and particularly between the right coronary artery and the left anterior descending artery. Resting membrane potential that contributes largely to the vascular tone is mainly regulated by K(+) channels in coronary myocytes. In the present study, we hypothesized that right coronary artery (RCA) and left coronary artery (LCA) exhibited a cell-specific function of K(+) channels. The net outward current was markedly greater in RCA compared with LCA cells, and this difference was due to a larger 4-aminopyridine (4-AP)-sensitive voltage-gated potssium (Kv) current in RCA cells, whereas the iberiotoxin (IbTx)-sensitive, large conductance Ca(2+)-dependent potassium (BK(Ca)) current was smaller in RCA cells. To go further in the molecular identity of this Kv current, we used 50 nM correolide, which specifically blocked Kv1 family alpha-subunits. Outward currents generated by ramp depolarization protocols were highly sensitive to correolide in both RCA and LCA cells, suggesting that Kv1 contributed for a large part to the net outward current. 4-AP-induced contractions in isolated RCA, and LCA were greater than IbTx-induced contraction. Furthermore, the 4-AP-induced contraction in RCA was significantly greater than that in LCA, which is in agreement with the electrophysiological data. Finally, the Kv1.2 alpha-subunit but not the Kv1.5 was detected in both RCA and LCA using primary specific antibody in Western blotting and immunofluorescence assay, and expression of Kv1.2 alpha-subunit was markedly higher in RCA compared with LCA. In summary, we reported for the first time a heterogeneous function and expression of Kv1 alpha-subunits in rat coronary myocytes isolated from RCA or LCA.
Mesh Headings (Keywords): Animals, Cells, Cultured, Coronary Vessels, Heart Ventricles, Ion Channel Gating, Male, Membrane Potentials, Myocardial Contraction, Myocytes, Cardiac, Rats, Rats, Wistar, Shaker Superfamily of Potassium Channels
Check for Full Text / PubMed Unique Identifier (PMID): 16731637
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.