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Titolo:
CHARACTERIZATION OF THE HYPERPOLARIZATION-ACTIVATED INWARD CURRENT INISOLATED HUMAN ATRIAL MYOCYTES
Autore:
HOPPE UC; BEUCKELMANN DJ;
Indirizzi:
UNIV COLOGNE,DEPT MED 3,JOSEPH STELZMANN STR 9 D-50924 COLOGNE GERMANY
Titolo Testata:
Cardiovascular Research
fascicolo: 3, volume: 38, anno: 1998,
pagine: 788 - 801
SICI:
0008-6363(1998)38:3<788:COTHIC>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
RABBIT SINOATRIAL NODE; TERMINAL HEART-FAILURE; CAT RIGHT ATRIUM; HUMAN VENTRICULAR MYOCYTES; CARDIAC-PACEMAKER CURRENT; PACE-MAKER CURRENT; CURRENT IF; TRANSCATHETER ABLATION; RADIOFREQUENCY CURRENT; ABNORMAL AUTOMATICITY;
Keywords:
ION CHANNEL; PACEMAKER CURRENT; PATCH CLAMP; HUMAN ATRIAL MYOCYTE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
61
Recensione:
Indirizzi per estratti:
Citazione:
U.C. Hoppe e D.J. Beuckelmann, "CHARACTERIZATION OF THE HYPERPOLARIZATION-ACTIVATED INWARD CURRENT INISOLATED HUMAN ATRIAL MYOCYTES", Cardiovascular Research, 38(3), 1998, pp. 788-801

Abstract

Objective: The hyperpolarization-activated inward current (I-f) has been discussed to contribute to arrhythmias in rat hypertrophied and human failing ventricular myocardium. Cat atrial myocytes were found to exhibit variable size of I-f. In the present study, we evaluate characteristics of I-f in human atrial myocardium and investigate if human atria might exhibit any electrophysiological heterogeneity in the diastolic voltage range. Methods and results: The whole-cell patch-clamp technique was used to record I-f in isolated myocytes from 96 human right atrial appendages. I-f was observed in 95% (ruptured-patch; 141/146)to 100% (perforated-patch; 18/18) of myocytes showing typical currentproperties, i.e. time- and voltage-dependence, block by [Cs+](o), permeability for K+, Na+ and Li+, and current increase with raising [K+](o). Using the perforated-patch technique Boltzmann distributions yielded an activation threshold of -60 to -70 mV and half maximal activation at -89.3 +/- 0.7 mV (n = 18). Isoproterenol (10(-6) mol/l) shifted I-f activation by +7 mV (7/7) using the perforated-patch technique, butonly inconsistently shifted I-f activation using the ruptured-patch method (6/21). Based on the relative current size of I-f and I-K1 threecell types could be distinguished (n = 26). In myocytes with a prominent I-f, I-f density was found to be larger (in [K+](o) 25 mmol/l at -80 mV: -0.78 +/- 0.23 pApF(-1); n = 7) than in cells with predominant I-K1 (in [K+](o) 25 mmol/l at -80 mV: -0.02 +/- 0.01 pApF(-1); n = 4) (P < 0.05). Conclusions: I-f is present in most human atrial myocytes. Many current properties are similar to those described for If in mammalian pacemaker cells. The relative current size of I-f and I-K1 were found to be variable in different myocytes. Whether I-f may favor spontaneous diastolic depolarization in individual human atrial myocytes exhibiting predominantly I-f in vivo remains to be defined, as current size is very small under physiological [K+](o). (C) 1998 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 09:36:53