scholarly journals Delayed afterdepolarization‐induced triggered activity in cardiac purkinje cells mediated through cytosolic calcium diffusion waves

2019 ◽  
Vol 7 (24) ◽  
Author(s):  
Chirag Shah ◽  
Sohel Jiwani ◽  
Bijay Limbu ◽  
Seth Weinberg ◽  
Makarand Deo
Keyword(s):  
Purkinje Cells ◽  
Cytosolic Calcium ◽  
Triggered Activity ◽  
Diffusion Waves ◽  
Cardiac Purkinje Cells ◽  
Calcium Diffusion ◽  
Delayed Afterdepolarization

scholarly journals Role of Cytosolic Calcium Diffusion in Murine Cardiac Purkinje Cells

2016 ◽  
Vol 10s1 ◽  
pp. CMC.S39705
Author(s):  
Bijay Limbu ◽  
Kushal Shah ◽  
Seth H. Weinberg ◽  
Makarand Deo
Keyword(s):  
Purkinje Cells ◽  
Ventricular Myocytes ◽  
Ionic Current ◽  
Cytosolic Calcium ◽  
Diffusion Waves ◽  
Cardiac Purkinje Cells ◽  
Calcium Diffusion ◽  
Intracellular Ca ◽  
Diffusion Rates

Cardiac Purkinje cells (PCs) are morphologically and electrophysiologically different from ventricular myocytes and, importantly, exhibit distinct calcium (Ca2+) homeostasis. Recent studies suggest that PCs are more susceptible to action potential (AP) abnormalities than ventricular myocytes; however, the exact mechanisms are poorly understood. In this study, we utilized a detailed biophysical mathematical model of a murine PC to systematically examine the role of cytosolic Ca2+ diffusion in shaping the AP in PCs. A biphasic spatiotemporal Ca2+ diffusion process, as recorded experimentally, was implemented in the model. In this study, we investigated the role of cytosolic Ca2+ dynamics on AP and ionic current properties by varying the effective Ca2+ diffusion rate. It was observed that AP morphology, specifically the plateau, was affected due to changes in the intracellular Ca2+ dynamics. Elevated Ca2+ concentration in the sarcolemmal region activated inward sodium-Ca2+ exchanger (NCX) current, resulting in a prolongation of the AP plateau at faster diffusion rates. Artificially clamping the NCX current to control values completely reversed the alterations in the AP plateau, thus confirming the role of NCX in modifying the AP morphology. Our results demonstrate that cytosolic Ca2+ diffusion waves play a significant role in shaping APs of PCs and could provide mechanistic insights in the increased arrhythmogeneity of PCs.

Role of Cytosolic Calcium Diffusion and Sarcolemmal T-Type Calcium Current in Triggered Activity in Purkinje Cells: A Simulation Study

Heart Rhythm ◽  
2011 ◽  
Vol 8 (11) ◽  
pp. 1821
Author(s):  
M. Deo ◽  
S.V. Pandit ◽  
R. Vaidyanathan ◽  
R. OConnell ◽  
M. Milstein ◽  
...  
Keyword(s):  
Purkinje Cells ◽  
Simulation Study ◽  
Calcium Current ◽  
Cytosolic Calcium ◽  
Triggered Activity ◽  
Calcium Diffusion

scholarly journals Ryanodine receptor gating controls generation of diastolic calcium waves in cardiac myocytes

2015 ◽  
Vol 145 (6) ◽  
pp. 489-511 ◽  
Author(s):  
Pavol Petrovič ◽  
Ivan Valent ◽  
Elena Cocherová ◽  
Jana Pavelková ◽  
Alexandra Zahradníková
Keyword(s):  
Ryanodine Receptor ◽  
Calcium Sensitivity ◽  
Cytosolic Calcium ◽  
Calcium Waves ◽  
Calcium Sparks ◽  
Calcium Spark ◽  
Gating Model ◽  
Calcium Diffusion ◽  
Confocal Scanning ◽  
Deterministic Description

The role of cardiac ryanodine receptor (RyR) gating in the initiation and propagation of calcium waves was investigated using a mathematical model comprising a stochastic description of RyR gating and a deterministic description of calcium diffusion and sequestration. We used a one-dimensional array of equidistantly spaced RyR clusters, representing the confocal scanning line, to simulate the formation of calcium sparks. Our model provided an excellent description of the calcium dependence of the frequency of diastolic calcium sparks and of the increased tendency for the production of calcium waves after a decrease in cytosolic calcium buffering. We developed a hypothesis relating changes in the propensity to form calcium waves to changes of RyR gating and tested it by simulation. With a realistic RyR gating model, increased ability of RyR to be activated by Ca2+ strongly increased the propensity for generation of calcium waves at low (0.05–0.1-µM) calcium concentrations but only slightly at high (0.2–0.4-µM) calcium concentrations. Changes in RyR gating altered calcium wave formation by changing the calcium sensitivity of spontaneous calcium spark activation and/or the average number of open RyRs in spontaneous calcium sparks. Gating changes that did not affect RyR activation by Ca2+ had only a weak effect on the propensity to form calcium waves, even if they strongly increased calcium spark frequency. Calcium waves induced by modulating the properties of the RyR activation site could be suppressed by inhibiting the spontaneous opening of the RyR. These data can explain the increased tendency for production of calcium waves under conditions when RyR gating is altered in cardiac diseases.

Electrophysiological Characteristics of Arterially-Perfused Canine Pulmonary Veins: Role of the Delayed Afterdepolarization-Induced Triggered Activity

2005 ◽  
Vol 35 (9) ◽  
pp. 643 ◽  
Author(s):  
Gi Byoung Nam ◽  
Kee Joon Choi ◽  
Duk Woo Park ◽  
Jun Kim ◽  
Kyung Suk Rhee ◽  
...  
Keyword(s):  
Pulmonary Veins ◽  
Triggered Activity ◽  
Delayed Afterdepolarization

Volumetric properties of intracellular compartments in canine cardiac Purkinje cells

1980 ◽  
Vol 238 (4) ◽  
pp. H561-H568
Author(s):  
S. R. Houser ◽  
A. R. Freeman
Keyword(s):  
Purkinje Cells ◽  
Regression Line ◽  
Resting Potential ◽  
Volumetric Properties ◽  
Bathing Medium ◽  
Cellular Volume ◽  
Cardiac Purkinje Fibers ◽  
Cardiac Purkinje Cells ◽  
Intracellular Compartments ◽  
The Relationship

Volumetric properties of canine cardiac Purkinje fibers were examined. Purkinje cells were superfused with anisosmolar solutions, and changes in extracellular space and relative cell volume were determined. The relationship between cellular volume and the osmolarity of the bathing medium was shown to be linear except in solutions of very low osmolarity. A linear regression line crossed the volume axis at 38%, suggesting an osmometric dead space of 38% and correspondingly an osmometric compartment comprising about 62% of the cell interior. To determine the volumetric properties of the "electrophysiological compartment," Purkinje cells were impaled with voltage-sensitive microelectrodes, and cellular resting potentials were recorded. When log K was plotted against resting potential (Em) in preparations bathed in normal and hyperosmotic solutions, it was shown that Em was increased in hyperosmotic solutions (13.5 and 21 mV in 600 and 850 mosM solutions, respectively). Calculations using the Nernst equation showed that the compartment containing the intracellular K involved in membrane electrical events behaves as a near-perfect osmometer in hyperosmotic solutions. Changes in the osmometric compartment were well correlated with K changes in the electrophysiological compartment, thus suggesting that the K is homogeneously distributed intracellularly.

Cardiac purkinje cells in culture

1984 ◽  
Vol 16 ◽  
pp. iv-iv
Author(s):  
E CANALE ◽  
J CAMPBELL ◽  
G CAMPBELL
Keyword(s):  
Purkinje Cells ◽  
Cells In Culture ◽  
Cardiac Purkinje Cells

scholarly journals Isolation and Characterization of Embryonic Stem Cell-Derived Cardiac Purkinje Cells

Stem Cells ◽  
2015 ◽  
Vol 33 (4) ◽  
pp. 1102-1112 ◽  
Author(s):  
Karen Maass ◽  
Akshay Shekhar ◽  
Jia Lu ◽  
Guoxin Kang ◽  
Fiona See ◽  
...  
Keyword(s):  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Purkinje Cells ◽  
Embryonic Stem ◽  
Isolation And Characterization ◽  
Cardiac Purkinje Cells
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