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Cellular electrophysiology of canine pulmonary vein cardiomyocytes: action potential and ionic current properties.
J Physiol. 2003 Sep 15; 551(Pt 3):801-13.JP

Abstract

Pulmonary vein (PV) cardiomyocytes play an important role in atrial fibrillation; however, little is known about their specific cellular electrophysiological properties. We applied standard microelectrode recording and whole-cell patch-clamp to evaluate action potentials and ionic currents in canine PVs and left atrium (LA) free wall. Resting membrane potential (RMP) averaged -66 +/- 1 mV in PVs and -74 +/- 1 mV in LA (P < 0.0001) and action potential amplitude averaged 76 +/- 2 mV in PVs vs. 95 +/- 2 mV in LA (P < 0.0001). PVs had smaller maximum phase 0 upstroke velocity (Vmax: 98 +/- 9 vs. 259 +/- 16 V s(-1), P < 0.0001) and action potential duration (APD): e.g. at 2 Hz, APD to 90% repolarization in PVs was 84 % of LA (P < 0.05). Na+ current density under voltage-clamp conditions was similar in PV and LA, suggesting that smaller Vmax in PVs was due to reduced RMP. Inward rectifier current density in the PV cardiomyocytes was approximately 58% that in the LA, potentially accounting for the less negative RMP in PVs. Slow and rapid delayed rectifier currents were greater in the PV (by approximately 60 and approximately 50 %, respectively), whereas transient outward K+ current and L-type Ca2+ current were significantly smaller (by approximately 25 and approximately 30%, respectively). Na(+)-Ca(2+)-exchange (NCX) current and T-type Ca2+ current were not significantly different. In conclusion, PV cardiomyocytes have a discrete distribution of transmembrane ion currents associated with specific action potential properties, with potential implications for understanding PV electrical activity in cardiac arrhythmias.

Authors+Show Affiliations

Department of Medicine and Research Center, Montreal Heart Institute and University of Montreal, Montreal, Quebec, Canada.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

12847206

Citation

Ehrlich, Joachim R., et al. "Cellular Electrophysiology of Canine Pulmonary Vein Cardiomyocytes: Action Potential and Ionic Current Properties." The Journal of Physiology, vol. 551, no. Pt 3, 2003, pp. 801-13.
Ehrlich JR, Cha TJ, Zhang L, et al. Cellular electrophysiology of canine pulmonary vein cardiomyocytes: action potential and ionic current properties. J Physiol. 2003;551(Pt 3):801-13.
Ehrlich, J. R., Cha, T. J., Zhang, L., Chartier, D., Melnyk, P., Hohnloser, S. H., & Nattel, S. (2003). Cellular electrophysiology of canine pulmonary vein cardiomyocytes: action potential and ionic current properties. The Journal of Physiology, 551(Pt 3), 801-13.
Ehrlich JR, et al. Cellular Electrophysiology of Canine Pulmonary Vein Cardiomyocytes: Action Potential and Ionic Current Properties. J Physiol. 2003 Sep 15;551(Pt 3):801-13. PubMed PMID: 12847206.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cellular electrophysiology of canine pulmonary vein cardiomyocytes: action potential and ionic current properties. AU - Ehrlich,Joachim R, AU - Cha,Tae-Joon, AU - Zhang,Liming, AU - Chartier,Denis, AU - Melnyk,Peter, AU - Hohnloser,Stefan H, AU - Nattel,Stanley, Y1 - 2003/07/07/ PY - 2003/7/9/pubmed PY - 2004/5/28/medline PY - 2003/7/9/entrez SP - 801 EP - 13 JF - The Journal of physiology JO - J Physiol VL - 551 IS - Pt 3 N2 - Pulmonary vein (PV) cardiomyocytes play an important role in atrial fibrillation; however, little is known about their specific cellular electrophysiological properties. We applied standard microelectrode recording and whole-cell patch-clamp to evaluate action potentials and ionic currents in canine PVs and left atrium (LA) free wall. Resting membrane potential (RMP) averaged -66 +/- 1 mV in PVs and -74 +/- 1 mV in LA (P < 0.0001) and action potential amplitude averaged 76 +/- 2 mV in PVs vs. 95 +/- 2 mV in LA (P < 0.0001). PVs had smaller maximum phase 0 upstroke velocity (Vmax: 98 +/- 9 vs. 259 +/- 16 V s(-1), P < 0.0001) and action potential duration (APD): e.g. at 2 Hz, APD to 90% repolarization in PVs was 84 % of LA (P < 0.05). Na+ current density under voltage-clamp conditions was similar in PV and LA, suggesting that smaller Vmax in PVs was due to reduced RMP. Inward rectifier current density in the PV cardiomyocytes was approximately 58% that in the LA, potentially accounting for the less negative RMP in PVs. Slow and rapid delayed rectifier currents were greater in the PV (by approximately 60 and approximately 50 %, respectively), whereas transient outward K+ current and L-type Ca2+ current were significantly smaller (by approximately 25 and approximately 30%, respectively). Na(+)-Ca(2+)-exchange (NCX) current and T-type Ca2+ current were not significantly different. In conclusion, PV cardiomyocytes have a discrete distribution of transmembrane ion currents associated with specific action potential properties, with potential implications for understanding PV electrical activity in cardiac arrhythmias. SN - 0022-3751 UR - https://www.unboundmedicine.com/medline/citation/12847206/Cellular_electrophysiology_of_canine_pulmonary_vein_cardiomyocytes:_action_potential_and_ionic_current_properties_ L2 - https://doi.org/10.1113/jphysiol.2003.046417 DB - PRIME DP - Unbound Medicine ER -