We used numerical integration techniques to simulate action potential propagation along one-dimensional strands of cells coupled with electrical junctions. We considered the standard case to be a series of cardiac cells (20 micrometer in diameter, 50 micrometers long) with intercellular coupling such that the effective longitudinal resistance was 200 omega cm. The membrane properties were repre...

To investigate the dynamics and propensity for arrhythmias in intact transgenic hearts comprehensively, optical strategies for panoramic fluorescence imaging of action potential (AP) propagation are essential. In particular, mechanism-oriented molecular studies usually depend on transgenic mouse hearts of only a few millimeters in size. Furthermore, the temporal scales of the mouse heart remain...

Acknowledgments We are grateful to S.N. Baker for organizing the EPSRCfunded Newcastle workshop on Spike Train Analysis, which inspired the writing of this review. We thank M. Diamond and E. Arabzadeh for sharing their data, and P.E. Latham, L. Paninski and J.D. Victor for useful discussions and insightful comments. Our research was supported by Pfizer Global Development (SP,RS), EPSRC EP/C0108...

1. The properties of whole-cell and single-channel Na+ and K+ currents in immunocytochemically identified bovine lactotrophs were studied using the patch-clamp technique. 2. In the whole-cell, current-clamp mode, cells had membrane potentials of -94.7 +/- 6.7 mV and input resistances of 2-17 G omega. Current-induced action potentials were recorded with a threshold around -35 mV and amplitude of...

Three-dimensional membrane-based simulations of action potential propagation in ventricular myocardium were performed. Specifically, the effects of the intramural rotation of the fiber axes and inhomogeneous conductivity on the timing and pattern of epicardial activation were examined. Models were built, with approximately 400,000 microscopic elements arranged in rectangular parallelepipeds in ...

The inclusion of nonconducting media, mimicking cardiac fibrosis, in two models of cardiac tissue produces the formation of ectopic beats. The fraction of nonconducting media in comparison with the fraction of healthy myocytes and the topological distribution of cells determines the probability of ectopic beat generation. First, a detailed subcellular microscopic model that accounts for the mic...

Real-time mapping and manipulation of electrophysiology in three-dimensional (3D) tissues could have important impacts on fundamental scientific and clinical studies, yet realization is hampered by a lack of effective methods. Here we introduce tissue-scaffold-mimicking 3D nanoelectronic arrays consisting of 64 addressable devices with subcellular dimensions and a submillisecond temporal resolu...

To examine some possible sites of fatigue during short-lasting maximally intensive stretch-shortening cycle exercise, drop jumps on an inclined sledge apparatus were analyzed. Twelve healthy volunteers performed jumps until they were unable to maintain jumping height > 90% of their maximum. After the workout, the increases in the blood lactate concentration and serum creatine kinase activation ...

Myelinated axons are organized into a series of specialized domains with distinct molecular compositions and functions. These domains, which include the node of Ranvier, the flanking paranodal junctions, the juxtaparanodes, and the internode, form as the result of interactions with myelinating Schwann cells. This domain organization is essential for action potential propagation by saltatory con...

Two main mechanisms have been suggested for the propagation of action potentials in cardiac muscle cells: (1) the free flow of local circuit current through gap junctions and (2) the effect of electrical field. Different evidences confirm each of two mechanisms. We think that gap junctions are not continuously open in a normal heart cycle; instead, they open and close intermittently. In other w...