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In heart, the propagation of electrical activity is mediated by intercellular channels, referred to as junctional channels, aggregated into gap junctions and localised between myocytes. These channels consist of structurally related transmembrane proteins, the connexins, three of which (CX43, CX40 and CX45) have been shown to be associated with the myocytes(More)
Connexins, the protein molecules forming gap junction channels, are reduced in number or redistributed from intercalated disks to lateral cell borders in a variety of cardiac diseases. This "gap junction remodeling" is considered to be arrhythmogenic. Using a simple model of human ventricular myocardium, we found that quantitative remodeling data extracted(More)
Cultures of neonatal rat heart cells contain predominantly myocytes and fibroblastic cells. Most abundant are groups of synchronously contracting myocytes, which are electrically well coupled through large gap junctions. Cardiac fibroblasts may be electrically coupled to each other and to adjacent myocytes, be it with low intercellular conductances.(More)
Genetic approaches have succeeded in defining the molecular basis of an increasing array of heart diseases, such as hypertrophic cardiomyopathy and the long-QT syndromes, associated with serious arrhythmias. Importantly, the way in which this new knowledge can be applied to managing patients and to the development of syndrome-specific antiarrhythmic(More)
Short-term (10 min) effects of 100 nM 12-O-tetradecanoylphorbol-13-acetate (TPA), the protein kinase C (PKC) activator, on cardiac macroscopic (gj) and single channel (gamma j) gap junctional conductances were studied in pairs of neonatal rat cardiomyocytes. Under dual whole-cell (WC) or perforated patch (PP) voltage-clamp, gj increased by 15.5 +/- 7.2%(More)
The electrical properties of gap junctions in cell pairs are usually studied by means of the dual voltage clamp method. The voltage across the junctional channels, however, cannot be controlled adequately due to an artificial resistance and a natural resistance, both connected in series with the gap junction. The access resistances to the cell interior of(More)
Connexin40 (Cx40) is a member of the connexin family of gap junction proteins. Its mRNA, abundant in lung, is also present in mammalian heart, although in lower amount. Rabbit antipeptide antibodies directed to the COOH terminus (residues 335 to 356) of rat Cx40 were characterized to investigate the distribution of Cx40 in rat and guinea pig cardiac(More)
In this study we report about the modulation of connexin45 (Cx45) gap junction channel properties by phosphorylation of the connexin molecules through different protein kinases. Phosphorylation of Cx45 was studied in HeLa cells transfected with mouse Cx45 (mCx45). Using Western blotting (WB) and immunocytochemistry, these cells were found exclusively(More)
Using immunohistochemical staining, the distribution of connexin40 (Cx40) and connexin43 (Cx43) was studied in rat, guinea pig, porcine, bovine and human hearts. These species display differences in the degree of morphological differentiation of the conduction system. This study was performed in the anticipation that comparison of the distributions of Cx40(More)
In the past decade, three mathematical models describing the pacemaker activity of the rabbit sinoatrial node have been developed: the Bristow-Clark model, the Irisawa-Noma model, and the Noble-Noble model. In a comparative study it is demonstrated that these models, as well as subsequent modifications, all have several drawbacks. A more accurate model,(More)