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Titolo:
Potential ionic mechanism for repolarization differences between canine right and left atrium
Autore:
Li, DS; Zhang, LM; Kneller, J; Nattel, S;
Indirizzi:
Montreal Heart Inst, Res Ctr, Montreal, PQ H1T 1C8, Canada Montreal Heart Inst Montreal PQ Canada H1T 1C8 ntreal, PQ H1T 1C8, Canada Montreal Heart Inst, Dept Med, Montreal, PQ H1T 1C8, Canada Montreal HeartInst Montreal PQ Canada H1T 1C8 ntreal, PQ H1T 1C8, Canada Univ Montreal, Montreal, PQ, Canada Univ Montreal Montreal PQ CanadaUniv Montreal, Montreal, PQ, Canada McGill Univ, Dept Pharmacol & Therapeut, Montreal, PQ, Canada McGill UnivMontreal PQ Canada armacol & Therapeut, Montreal, PQ, Canada
Titolo Testata:
CIRCULATION RESEARCH
fascicolo: 11, volume: 88, anno: 2001,
pagine: 1168 - 1175
SICI:
0009-7330(20010608)88:11<1168:PIMFRD>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
MITRAL-VALVE DISEASE; ISOLATED SHEEP HEART; ELECTROPHYSIOLOGICAL CHARACTERISTICS; REGIONAL DIFFERENCES; PULMONARY VEINS; FIBRILLATION; INITIATION; MODEL; SUSCEPTIBILITY; DOFETILIDE;
Keywords:
channels; heterogeneity; electrophysiology;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Nattel, S Montreal Heart Inst, Res Ctr, 5000 Belanger St E, Montreal, PQ H1T 1C8, Canada Montreal Heart Inst 5000 Belanger St E Montreal PQ Canada H1T 1C8
Citazione:
D.S. Li et al., "Potential ionic mechanism for repolarization differences between canine right and left atrium", CIRCUL RES, 88(11), 2001, pp. 1168-1175

Abstract

Experimental and clinical evidence suggests a critical role for the left atrium (LA) in atrial fibrillation (AF), In animal models, repolarization isfaster in the LA than in the right atrium (RA), leading to more stable reentry circuits with a shorter intrinsic period in the LA. The ionic mechanisms underlying LA-RA repolarization differences are unknown, Therefore, we evaluated ionic currents and action potentials (APs) with the whole-cell patch clamp in isolated canine atrial myocytes. The density of the rapid delayed rectifier current (I-Kr) was greater in the LA leg, 1.83 +/-0.10 pA/pF at +20 mV) than in the RA (1.15 +/-0.07 pA/pF, P <0.01; n=16 cells per group). The slow and ultrarapid delayed rectifier, the inward rectifier, L-type Ca2+, and transient outward K+ currents were all comparable in the LA and RA. There were no differences in kinetic or voltage-dependent properties of currents in LA versus RA, Western blots of ether-a-go-go-related gene (ERG)protein in three RA and corresponding LA regions showed significantly greater ERG expression in LA. AP duration (APD) was shorter in the LA versus RAin both isolated cells and multicellular preparations, and the effective refractory period (ERP) was shorter in the LA compared with the RA in vivo, Dofetilide had significantly larger APD- and ERP-increasing effects in the LA compared with RA, and LA-RA repolarization differences were eliminated by exposure to dofetilide, We conclude that LA myocytes have larger I-Kr than do RA myocytes, contributing importantly to the shorter APD and ERP in LA. The larger LA I-Kr may participate in the ability of the LA to act as a "driver region" for AF, with potentially important implications for understanding AF mechanisms and antiarrhythmic therapy.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 11/07/20 alle ore 13:04:59