Model number


A mathematical model of a rabbit sinoatrial node cell. Demir, S., J. Clark, C. Murphey, and W. Giles. Am. J. Physiol. Cell Physiol. 266: C832-C852, 1994.



A mathematical model for the electrophysiological 
responses of a rabbit sinoatrial node cell that is 
based on whole cell recordings from enzymatically 
isolated single pacemaker cells at 37 degrees C has 
been developed. The ion channels, Na(+)-K+ and Ca2+ 
pumps, and Na+-Ca2+ exchanger in the surface membrane 
(sarcolemma) are described using equations for these 
known currents in mammalian pacemaker cells.  The 
extracellular environment is treated as a diffusion-
limited space, and the myoplasm contains Ca2+-binding 
proteins (calmodulin and troponin). Original features 
of this model include 1) new equations for the hyper-
polarization-activated inward current, 2) assessment 
of the role of the transient-type Ca2+ current during 
pacemaker depolarization, 3) inclusion of an Na+ 
current based on recent experimental data, and 4) 
demonstration of the possible influence of pump and 
exchanger currents and background currents on the 
pacemaker rate. This model provides acceptable fits
to voltage-clamp and action potential data and can be 
used to seek biophysically based explanations of the 
electrophysiological activity in the rabbit sinoatrial 
node cell. 

   CellML models are found at:
The nature of CellML combined with the program trans-
lating CellML (a variant of xml) into JSim's MML gives 
a surfeit of parentheses, and unfortunately loses any 
Commments and definitions that may have been in CellML.


The equations for this model may be viewed by running the JSim model applet and clicking on the Source tab at the bottom left of JSim's Run Time graphical user interface. The equations are written in JSim's Mathematical Modeling Language (MML). See the Introduction to MML and the MML Reference Manual. Additional documentation for MML can be found by using the search option at the Physiome home page.

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 Demir, S., J. Clark, C. Murphey, and W. Giles. A mathematical model
 of a rabbit sinoatrial node cell.  Am. J. Physiol. Cell Physiol.
 266: C832-C852, 1994.

Demir, Semahat S., John W. Clark, and Wayne R.Giles. Parasympathetic modulation of sinoatrial node pacemaker activity in rabbit heart: a unifying model. Am J Physiol Heart Circ 276: H2221-H2244, 1999.

Pandit SV, Clark RB, Giles WR, and Demir SS. A mathematical model of action potential heterogeneity in adult rat left ventricular myocytes. Biophys J 81: 3029-3051, 2001. Kurata, Yasutaka, Ichiro Hisatome, Sunao Imanishi,and Toshishige Shibamoto. Dynamical description of sinoatrial node pacemaking: improved mathematical model for primary pacemaker cell. Am J Physiol Heart Circ Physiol 283: H2074-H2101, 2002.

Key terms
action potential simulation
muscarinic receptors
junctional receptor
extrajunctional receptor
phase sensitivity
phase-response curve
steady-state entrainment
cardiac pacemaker cell
whole cell voltage clamp
Hodgkin-Huxley model

Please cite in any publication for which this software is used and send one reprint to the address given below:
The National Simulation Resource, Director J. B. Bassingthwaighte, Department of Bioengineering, University of Washington, Seattle WA 98195-5061.

Model development and archiving support at provided by the following grants: NIH U01HL122199 Analyzing the Cardiac Power Grid, 09/15/2015 - 05/31/2020, NIH/NIBIB BE08407 Software Integration, JSim and SBW 6/1/09-5/31/13; NIH/NHLBI T15 HL88516-01 Modeling for Heart, Lung and Blood: From Cell to Organ, 4/1/07-3/31/11; NSF BES-0506477 Adaptive Multi-Scale Model Simulation, 8/15/05-7/31/08; NIH/NHLBI R01 HL073598 Core 3: 3D Imaging and Computer Modeling of the Respiratory Tract, 9/1/04-8/31/09; as well as prior support from NIH/NCRR P41 RR01243 Simulation Resource in Circulatory Mass Transport and Exchange, 12/1/1980-11/30/01 and NIH/NIBIB R01 EB001973 JSim: A Simulation Analysis Platform, 3/1/02-2/28/07.