Phenotypical features of long Q-T syndrome in transgenic mice expressing human Na-K-ATPase alpha(3)-isoform in hearts.
Am J Physiol Heart Circ Physiol
; 279(5): H2133-42, 2000 Nov.
Article
en En
| MEDLINE
| ID: mdl-11045946
To understand why the adult human heart expresses three isoforms of the sodium pump, we generated transgenic mice (TGM) with 2.3- to 5. 5-fold overexpression of the human alpha(3)-isoform of Na-K-ATPase in the heart. Hearts from the TGM had increased maximal Na-K-ATPase activity and ouabain affinity compared with control hearts, even though the density of Na-K-ATPase pump sites (of all isoforms) was similar to that of control mice. In perfused hearts, contractility both at baseline and in the presence of ouabain tended to be greater in TGM than in controls. Surface electrocardiograms in anesthetized TGM had a steeper dependence of Q-T on sinus cycle length, and Q-T intervals measured during atrial pacing were significantly longer in TGM. Q-T dispersion during sinus rhythm also tended to be longer in TGM. Thus TGM overexpressing human alpha(3)-isoform have several of the phenotypical features of human long Q-T syndrome, despite the absence of previously described mutations in Na(+) or K(+) channels.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Síndrome de QT Prolongado
/
ATPasa Intercambiadora de Sodio-Potasio
/
Miocardio
Tipo de estudio:
Etiology_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Am J Physiol Heart Circ Physiol
Asunto de la revista:
CARDIOLOGIA
/
FISIOLOGIA
Año:
2000
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos