scholarly journals Effect of Ca2+Efflux Pathway Distribution and Exogenous Ca2+Buffers on Intracellular Ca2+Dynamics in the Rat Ventricular Myocyte: A Simulation Study

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Michal Pásek ◽  
Jiří Šimurda ◽  
Clive H. Orchard
Keyword(s):  
Computer Model ◽  
Simulation Study ◽  
Ventricular Myocyte ◽  
Dependent Inactivation ◽  
Dyadic Space ◽  
Efflux Pathway ◽  
Rat Ventricular Myocyte ◽  
Cellular Ca

We have used a previously published computer model of the rat cardiac ventricular myocyte to investigate the effect of changing the distribution of Ca2+efflux pathways (SERCA, Na+/Ca2+exchange, and sarcolemmal Ca2+ATPase) between the dyad and bulk cytoplasm and the effect of adding exogenous Ca2+buffers (BAPTA or EGTA), which are used experimentally to differentially buffer Ca2+in the dyad and bulk cytoplasm, on cellular Ca2+cycling. Increasing the dyadic fraction of a particular Ca2+efflux pathway increases the amount of Ca2+removed by that pathway, with corresponding changes in Ca2+efflux from the bulk cytoplasm. The magnitude of these effects varies with the proportion of the total Ca2+removed from the cytoplasm by that pathway. Differences in the response to EGTA and BAPTA, including changes in Ca2+-dependent inactivation of the L-type Ca2+current, resulted from the buffers acting as slow and fast “shuttles,” respectively, removing Ca2+from the dyadic space. The data suggest that complex changes in dyadic Ca2+and cellular Ca2+cycling occur as a result of changes in the location of Ca2+removal pathways or the presence of exogenous Ca2+buffers, although changing the distribution of Ca2+efflux pathways has relatively small effects on the systolic Ca2+transient.

Computer model of membrane current and intracellular Ca2+ flux in the isolated guinea pig ventricular myocyte

1994 ◽  
Vol 267 (5) ◽  
pp. 1-1 ◽  
Author(s):  
Charles Nordin
Keyword(s):  
Guinea Pig ◽  
Computer Program ◽  
Computer Model ◽  
Membrane Current ◽  
The Other ◽  
Ventricular Myocyte ◽  
Stimulation Rate ◽  
Intracellular Ca ◽  
Made In

Pages H2117–H2136: Nordin, Charles. “Computer model of membrane current and intracellular Ca2+ flux in the isolated guinea pig ventricular myocyte.” Figure 13: Units of time in Fig. 13B are seconds (not milliseconds). The output for concentration, using the equations of the appendix, is in units of 10−3 mol/l (millimolar). Equation A29 should read (See PDF) Equations A30a and A31a should read (See PDF) Note: All errors in equations, except for the term with asterisk in Eq. A31a and removal of the term (0.1 x iCa) from Eq. A30a, were made in transcribing the computer program to the set of printed equations and therefore do not involve any simulations of the paper. The other changes are refinements of the program that slightly reduce the rise in [Na+]myo and fall in [K+]myo with increasing stimulation rate (Fig. 5A) but do not affect other aspects of the behavior of the model in any significant way.

scholarly journals GPU-Enabled stochastic Spatiotemporal Model of Rat Ventricular Myocyte Calcium Dynamics

2011 ◽  
Vol 100 (3) ◽  
pp. 557a
Author(s):  
Tuan M. Hoang-Trong ◽  
George S.B. Williams ◽  
Jonathan W. Lederer ◽  
Saleet Jafri
Keyword(s):  
Ventricular Myocyte ◽  
Calcium Dynamics ◽  
Spatiotemporal Model ◽  
Rat Ventricular Myocyte

scholarly journals Anisotropic conduction block and reentry in neonatal rat ventricular myocyte monolayers

2011 ◽  
Vol 300 (1) ◽  
pp. H271-H278 ◽  
Author(s):  
Carlos de Diego ◽  
Fuhua Chen ◽  
Yuanfang Xie ◽  
Rakesh K. Pai ◽  
Leonid Slavin ◽  
...  
Keyword(s):  
Gap Junction ◽  
Conduction Block ◽  
Neonatal Rat ◽  
Fiber Direction ◽  
Ventricular Myocyte ◽  
Na Current ◽  
Current Availability ◽  
Rapid Pacing ◽  
Rat Ventricular Myocyte ◽  
Junction Conductance

Anisotropy can lead to unidirectional conduction block that initiates reentry. We analyzed the mechanisms in patterned anisotropic neonatal rat ventricular myocyte monolayers. Voltage and intracellular Ca (Cai) were optically mapped under the following conditions: extrastimulus (S1S2) testing and/or tetrodotoxin (TTX) to suppress Na current availability; heptanol to reduce gap junction conductance; and incremental rapid pacing. In anisotropic monolayers paced at 2 Hz, conduction velocity (CV) was faster longitudinally than transversely, with an anisotropy ratio [AR = CVL/CVT, where CVL and CVT are CV in the longitudinal and transverse directions, respectively], averaging 2.1 ± 0.8. Interventions decreasing Na current availability, such as S1S2 pacing and TTX, slowed CVL and CVT proportionately, without changing the AR. Conduction block preferentially occurred longitudinal to fiber direction, commonly initiating reentry. Interventions that decreased gap junction conductance, such as heptanol, decreased CVT more than CVL, increasing the AR and causing preferential transverse conduction block and reentry. Rapid pacing resembled the latter, increasing the AR and promoting transverse conduction block and reentry, which was prevented by the Cai chelator 1,2-bis oaminophenoxy ethane- N, N, N′, N′-tetraacetic acid (BAPTA). In contrast to isotropic and uniformly anisotropic monolayers, in which reentrant rotors drifted and self-terminated, bidirectional anisotropy (i.e., an abrupt change in fiber direction exceeding 45°) caused reentry to anchor near the zone of fiber direction change in 77% of monolayers. In anisotropic monolayers, unidirectional conduction block initiating reentry can occur longitudinal or transverse to fiber direction, depending on whether the experimental intervention reduces Na current availability or decreases gap junction conductance, agreeing with theoretical predictions.

Phospholipase a activity of cultured rat ventricular myocyte is affected by the nature of cellular polyunsaturated fatty acids

Lipids ◽  
1990 ◽  
Vol 25 (6) ◽  
pp. 301-306 ◽  
Author(s):  
Gilles Nalbone ◽  
Alain Grynberg ◽  
Annick Chevalier ◽  
Jeannie Leonardi ◽  
Elise Termine ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Polyunsaturated Fatty Acids ◽  
Phospholipase A ◽  
Ventricular Myocyte ◽  
Rat Ventricular Myocyte

scholarly journals Spatial Localisation and Function of pH-Regulatory Transporters in the Rat Ventricular Myocyte

2012 ◽  
Vol 102 (3) ◽  
pp. 143a
Author(s):  
Carolina Garciarena ◽  
Yu-Ling Ma ◽  
Pawel Swietach ◽  
Richard D. Vaughan-Jones
Keyword(s):  
Ventricular Myocyte ◽  
Spatial Localisation ◽  
And Function ◽  
Rat Ventricular Myocyte
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