Serge Viatchenko-Karpinski

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In contrast to terminally differentiated cardiomyocytes, relatively little is known about the characteristics of mammalian cardiac cells before the initiation of spontaneous contractions (precursor cells). Functional studies on these cells have so far been impossible because murine embryos of the corresponding stage are very small, and cardiac precursor(More)
Voltage-operated Ca2+ channels are heteromultimeric proteins. Their structural diversity is caused by several genes encoding homologous subunits and by alternative splicing of single transcripts. Isoforms of alpha1 subunits, which contain the ion conducting pore, have been deduced from each of the six cDNA sequences cloned so far from different species. The(More)
Activity of cardiac pacemaker cells is caused by a balanced interplay of ion channels. However, it is not known how the rhythmic beating is initiated during early stages of cardiomyogenesis, when the expression of ion channels is still incomplete. Based on the observation that early-stage embryonic stem cell-derived cardiomyocytes continuously contracted in(More)
AIMS Although cardiac alternans is a known predictor of lethal arrhythmias, its underlying causes remain largely undefined in disease settings. The potential role of, and mechanisms responsible for, beat-to-beat alternations in the amplitude of systolic Ca(2+) transients (Ca(2+) alternans) was investigated in a canine post-myocardial infarction (MI) model(More)
Mechanisms of impaired calcium handling underlying subclinical diastolic dysfunction in diabetes. diastolic dysfunction is found in almost half of asymptomatic patients with well-controlled diabetes and may precede diastolic heart failure. However, mechanisms that underlie diastolic dysfunction during diabetes are not well understood. We tested the(More)
1. To define the sub-cellular mechanisms of modulation of cardiac excitation-contraction (E-C) coupling by the beta-adrenergic pathway, we carried out confocal Ca(2+) imaging in conjunction with recordings of inward Ca(2+) current in fluo-3-loaded patch-clamped rat ventricular myocytes. 2. Isoproterenol (isoprenaline; ISO) increased the amplitude of the(More)
Single, murine embryonic stem cell-derived early stage cardiomyocytes dissociated from embryoid bodies expressed two inward rectifier K(+) channels, I(K1) and the ATP dependent K(+) current. I(K1) exhibited low density in early stage cardiomyocytes, but increased significantly in late stage cells. In contrast, the ATP dependent K(+) current was expressed at(More)
Nitric oxide (NO) and superoxide (O(2) (-)) are important cardiac signaling molecules that regulate myocyte contraction. For appropriate regulation, NO and O(2) (.-) must exist at defined levels. Unfortunately, the NO and O(2) (.-) levels are altered in many cardiomyopathies (heart failure, ischemia, hypertrophy, etc.) leading to contractile dysfunction and(More)
Aims: Cardiac alternans is a known predictor of cardiac arrhythmias and sudden cardiac death (SCD), but the underlying causes of alternans remain largely undefined in disease. The potential role of, and mechanisms responsible for, beat-to-beat alternations in the amplitude of systolic Ca 2+ transients (Ca 2+ alternans) were investigated in a canine(More)
  • Pompeo Gyorke, Silvia G Volpe, Dmitry Priori, Federica Terentyev, Giorgia Turcato, Nicoletta Valle +18 others
  • 2006
Background—Four distinct mutations in the human cardiac calsequestrin gene (CASQ2) have been linked to catechol-aminergic polymorphic ventricular tachycardia (CPVT). The mechanisms leading to the clinical phenotype are still poorly understood because only 1 CASQ2 mutation has been characterized in vitro. Methods and Results—We identified a homozygous 16-bp(More)