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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)
1. Single cells were isolated from rabbit sino-atrial (SA) node by enzymatic dissociation. Spontaneous action potentials and membrane currents were recorded using the whole-cell patch clamp technique to study the relationship between electrical activity and the size of the cells. 2. The size of SA node cells was estimated by measuring the cell capacitance.(More)
BACKGROUND The mortality and morbidity rates of various cardiovascular diseases differ between Western countries and Japan. The age- and gender-specific prevalence rate of atrial fibrillation (AF) in the general population of Japan was determined using the data from periodic health examinations in 2003. METHODS Data of 630,138 subjects aged 40 years or(More)
In order to study regional differences in membrane properties within the sinus node, we have investigated the electrical activity of small specimens of tissue (approximately 0.3 mm in diameter) that have been prepared from the central, transitional and peripheral areas of the rabbit sinus node. The action potential upstroke velocity and overshoot as well as(More)
1. The electrical activity of sinoatrial node cells is heterogeneous. To understand the reasons for this, the density of the delayed-rectifier K+ current and its two components, i(K,r) and i(K,s), as a function of the size (as measured by cell capacitance) of rabbit sinoatrial node cells was investigated using the whole-cell voltage-clamp technique at 35(More)
Transplant of immature cardiomyocytes is recently attracting a great deal of interest as a new experimental strategy for the treatment of failing hearts. Full understanding of normal cardiomyogenesis is essential to make this regenerative therapy feasible. We analyzed the molecular and functional changes of Ca(2+) handling proteins during development of the(More)
Sympathetic innervation is critical for effective cardiac function. However, the developmental and regulatory mechanisms determining the density and patterning of cardiac sympathetic innervation remain unclear, as does the role of this innervation in arrhythmogenesis. Here we show that a neural chemorepellent, Sema3a, establishes cardiac sympathetic(More)
Effects of ATP on junctional conductance (gj) were investigated in paired ventricular myocytes isolated from guinea pig hearts. One cell of the pair was voltage-clamped with a single-patch pipette, and gj was measured after the perforation of the nonjunctional membrane of the partner cell. The current-voltage relation of gj was linear between -30 and +30(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)