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Mathematical models of the action potential in the periphery and center of the rabbit sinoatrial (SA) node have been developed on the basis of published experimental data. Simulated action potentials are consistent with those recorded experimentally: the model-generated peripheral action potential has a more negative takeoff potential, faster upstroke, more(More)
This article focuses on the regional heterogeneity of the mammalian sinoatrial (SA) node in terms of cell morphology, pacemaker activity, action potential configuration and conduction, densities of ionic currents (i(Na), i(Ca,L), i(to), i(K,r), i(K,s) and i(f)), expression of gap junction proteins (Cx40, Cx43 and Cx45), autonomic regulation, and ageing.(More)
OBJECTIVE Heart failure in patients and in animal models is associated with action potential prolongation of the ventricular myocytes. Changes in several membrane currents have been already demonstrated to underlie this prolongation. However, information on the two components (I(Kr) and I(Ks)) of the delayed rectifier potassium current (I(K)) in rapid(More)
BACKGROUND There is an effort to build an anatomically and biophysically detailed virtual heart, and, although there are models for the atria and ventricles, there is no model for the sinoatrial node (SAN). For the SAN to show pacemaking and drive atrial muscle, theoretically, there should be a gradient in electrical coupling from the center to the(More)
The present study investigates the remodeling of gap junctional organization in relation to changes in anisotropic conduction properties in hypertrophied right ventricles (RVs) of rats with monocrotaline (MCT)-induced pulmonary hypertension. In contrast to controls that showed immunolocalization of connexin43 (Cx43) labeling largely confined to the(More)
Knowledge of the initiation of electrical and contractile activity in the embryonic heart relies to a large extent on data obtained in chicken. In recent years, molecular biological techniques have raised an interest in mouse physiology, including early embryonic development. We studied action potentials and the occurrence of one of the pacemaker currents,(More)
Gprotein-activated inwardly rectifying K+ channel (GIRK or Kir3) currents are inhibited by mechanical stretch of the cell membrane, but the underlying mechanisms are not understood. In Xenopus oocytes heterologously expressing GIRK channels, membrane stretch induced by 50% reduction of osmotic pressure caused a prompt reduction of GIRK1/4, GIRK1, and GIRK4(More)
The mechanism of nicorandil-induced large inward tail current (Itail) in single guinea-pig ventricular cells was investigated using the whole-cell patch-clamp technique. In the presence of 0.5-1.0 mM nicorandil, an activator of adenosine 5'-triphosphate (ATP)-sensitive K+ current (IKATP), a depolarization pulse causing a large outward current was followed(More)
AIMS Atrial dilatation and myocardial stretch are strongly associated with atrial fibrillation (AF). However, the mechanisms by which the three-dimensional (3D) atrial architecture and heterogeneous stretch contribute to AF perpetuation are incompletely understood. We compared AF dynamics during stretch-related AF (pressure: 12 cmH(2)O) in normal sheep(More)
OBJECTIVES Loss of cardiac cells and the anatomical or functional remodeling of intercellular coupling occur under several pathological conditions. We have assessed the significance of intercellular coupling for cell death. METHODS AND RESULTS Ventricular cells obtained from 1 day old Wistar rats were cultured. Apoptosis was detected by nick-end labeling.(More)