Friel, 1995

Model Status

This is the original unchecked version of the model imported from the previous CellML model repository, 24-Jan-2006.

Model Structure

[Ca²⁺]_i oscillations have been described in a variety of cells. They appear to be controlled by multiple mechanisms. In some excitable cells, oscillations reflect periodic depolarisation and increased Ca²⁺ entry across the plasma membrane. In others, oscillations are dominated by Ca²⁺ uptake and release by internal stores.

In his 1995 mathematical model, David D. Friel has studied caffeine-induced [Ca²⁺]_i oscillations in sympathetic neurons. In this cell type, oscillations reflect both Ca²⁺ transport across the plasma membrane and uptake and release by internal stores. This model builds on previous work by examining the net fluxes of Ca²⁺ across the plasma membrane and between the cytosol and the intracellular store, and by presenting a quantitative model that addresses how these fluxes can together account for a periodic steady state.

The model defines four Ca²⁺ fluxes (see the figure below): two are passive leaks - one representing Ca²⁺ entry into the cell (J_L1) and one representing Ca²⁺ release from the intracellular store into the cytosol (J_L2). The other two Ca²⁺ fluxes are driven against an electrochemical gradient by pumps; J_P1 represents Ca²⁺ extrusion from the cytosol and J_P2 represents Ca²⁺ uptake into the intracellular store from the cytosol. This mathematical model has been translated into a CellML description which can be downloaded in various formats as described in .

The complete original paper reference is cited below:

[Ca²⁺]_i Oscillations In Sympathetic Neurons, David D. Friel, 1995, Biophysical Journal , 68, 1752-1766. PubMed ID: 7612818

Schematic of the model indicating Ca2+ compartmentalization in the extracellular matrix, cytosol and the mitochondrial matrix and pathways for Ca2+ ion movement between the compartments.