This applet is used to simulate the auto-oscillatory activation of Purkinje cells using the 16-variable Di Francesco Noble model (Phil. Trans. R. Soc. Lond., B307, 353-398).

Using the applet, the myocyte can be simulated at various cycle lengths and the final APD and DI is calculated automatically. In addition, it is possible to visualize the currents, gate variables, and ionic concentrations.

Time indicates how long ones the simulation to run (in msec).

[Na]i, [K]o and gna, are the intracellular sodium concentration, extracellular potassium concentracion and sodium conductance. The initial value for each variable can be changed in their respective boxes.

Click "Start" to start the simulation. Use "Replot" to replot on the screen once a check box has been selected or a new value has been entered for [Na]i, [k]o or gna. Use "Plot Currents" to plot the various currents of the model.

Things to try:

• Change the values of gna to 80 and time to 66000 and you'll see alternans in action potential in the model.
• Click in the Ascii check box to obtain the voltage signal as a function of time. (Note that the larger the signal, the longer it takes for the window to appear.)