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Comparison of ion channel distribution and expression in cardiomyocytes of canine pulmonary veins versus left atrium.
Cardiovasc Res. 2005 Jan 01; 65(1):104-16.CR

Abstract

BACKGROUND

Cardiomyocytes in pulmonary vein (PV) sleeves are important in atrial fibrillation (AF), but underlying mechanisms are poorly understood. Pulmonary veins have different ionic current properties compared to left atrium, with pulmonary vein inward-rectifier currents being smaller and delayed-rectifier currents larger than in left atrium.

METHODS

Expression and distribution of the inward-rectifier subunits Kir2.1 and Kir2.3, the rapid delayed-rectifier alpha-subunit ERG, the slow delayed-rectifier alpha-subunit KvLQT1, the beta-subunit minK, the L-type Ca(2+)-subunit Ca(v)1.2, and the Na(+),Ca(2+)-exchanger were quantified by Western blot on isolated cardiomyocytes and localized by immunohistochemistry in tissue sections obtained from canine hearts.

RESULTS

Western blotting indicated significantly greater expression of ERG (by 28%, P<0.05) and KvLQT1 (by 34%, P<0.05) in pulmonary vein versus left atrial (LA) cardiomyocytes, but smaller Kir2.3 and similar Kir2.1, Ca(v)1.2 and Na(+),Ca(2+)-exchanger expression in PV. Kir2.1 exhibited weak transverse tubular distribution in both regions. Kir2.3 localized to intercalated disks in both regions, and to transverse tubules in left atrium but not pulmonary vein. ERG staining was more intense in pulmonary vein than left atrium, localizing to transverse tubules in both regions and intercalated disks in pulmonary veins. KvLQT1 was more intensely expressed in pulmonary veins, with a transverse tubular and intercalated disk localization, versus a more diffuse signal in left atrium. The Na(+),Ca(2+)-exchanger localized to transverse tubules, plasma membranes and intercalated disks with similar intensity in each region.

CONCLUSIONS

Greater ERG and KvLQT1 abundance in pulmonary vein cardiomyocytes, lower abundance of Kir2.3 in pulmonary veins and differential pulmonary vein subcellular distribution of Kir2.3, ERG and KvLQT1 subunits may contribute to ionic current differences between pulmonary vein and left atrial cardiomyocytes.

Authors+Show Affiliations

Research Center, Montreal Heart Institute, 5000 Belanger Street East, Montreal, Quebec, Canada H1T 1C8.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15621038

Citation

Melnyk, Peter, et al. "Comparison of Ion Channel Distribution and Expression in Cardiomyocytes of Canine Pulmonary Veins Versus Left Atrium." Cardiovascular Research, vol. 65, no. 1, 2005, pp. 104-16.
Melnyk P, Ehrlich JR, Pourrier M, et al. Comparison of ion channel distribution and expression in cardiomyocytes of canine pulmonary veins versus left atrium. Cardiovasc Res. 2005;65(1):104-16.
Melnyk, P., Ehrlich, J. R., Pourrier, M., Villeneuve, L., Cha, T. J., & Nattel, S. (2005). Comparison of ion channel distribution and expression in cardiomyocytes of canine pulmonary veins versus left atrium. Cardiovascular Research, 65(1), 104-16.
Melnyk P, et al. Comparison of Ion Channel Distribution and Expression in Cardiomyocytes of Canine Pulmonary Veins Versus Left Atrium. Cardiovasc Res. 2005 Jan 1;65(1):104-16. PubMed PMID: 15621038.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparison of ion channel distribution and expression in cardiomyocytes of canine pulmonary veins versus left atrium. AU - Melnyk,Peter, AU - Ehrlich,Joachim R, AU - Pourrier,Marc, AU - Villeneuve,Louis, AU - Cha,Tae-Joon, AU - Nattel,Stanley, PY - 2004/03/10/received PY - 2004/07/30/revised PY - 2004/08/16/accepted PY - 2004/12/29/pubmed PY - 2005/3/3/medline PY - 2004/12/29/entrez SP - 104 EP - 16 JF - Cardiovascular research JO - Cardiovasc Res VL - 65 IS - 1 N2 - BACKGROUND: Cardiomyocytes in pulmonary vein (PV) sleeves are important in atrial fibrillation (AF), but underlying mechanisms are poorly understood. Pulmonary veins have different ionic current properties compared to left atrium, with pulmonary vein inward-rectifier currents being smaller and delayed-rectifier currents larger than in left atrium. METHODS: Expression and distribution of the inward-rectifier subunits Kir2.1 and Kir2.3, the rapid delayed-rectifier alpha-subunit ERG, the slow delayed-rectifier alpha-subunit KvLQT1, the beta-subunit minK, the L-type Ca(2+)-subunit Ca(v)1.2, and the Na(+),Ca(2+)-exchanger were quantified by Western blot on isolated cardiomyocytes and localized by immunohistochemistry in tissue sections obtained from canine hearts. RESULTS: Western blotting indicated significantly greater expression of ERG (by 28%, P<0.05) and KvLQT1 (by 34%, P<0.05) in pulmonary vein versus left atrial (LA) cardiomyocytes, but smaller Kir2.3 and similar Kir2.1, Ca(v)1.2 and Na(+),Ca(2+)-exchanger expression in PV. Kir2.1 exhibited weak transverse tubular distribution in both regions. Kir2.3 localized to intercalated disks in both regions, and to transverse tubules in left atrium but not pulmonary vein. ERG staining was more intense in pulmonary vein than left atrium, localizing to transverse tubules in both regions and intercalated disks in pulmonary veins. KvLQT1 was more intensely expressed in pulmonary veins, with a transverse tubular and intercalated disk localization, versus a more diffuse signal in left atrium. The Na(+),Ca(2+)-exchanger localized to transverse tubules, plasma membranes and intercalated disks with similar intensity in each region. CONCLUSIONS: Greater ERG and KvLQT1 abundance in pulmonary vein cardiomyocytes, lower abundance of Kir2.3 in pulmonary veins and differential pulmonary vein subcellular distribution of Kir2.3, ERG and KvLQT1 subunits may contribute to ionic current differences between pulmonary vein and left atrial cardiomyocytes. SN - 0008-6363 UR - https://www.unboundmedicine.com/medline/citation/15621038/Comparison_of_ion_channel_distribution_and_expression_in_cardiomyocytes_of_canine_pulmonary_veins_versus_left_atrium_ DB - PRIME DP - Unbound Medicine ER -