An electrodiffusive formalism was developed for computing the dynamics of the membrane potential and ion concentrations in the intra- and extracellular space in a one-dimensional geometry (cable). This (general) formalism was implemented in a model of astrocytes exchanging K+, Na+ and Cl- ions with the extracellular space (ECS). A limited region (0< x<l/10 where l is the astrocyte length) of the ECS was exposed to an increase in the local K+ concentration. The model is used to explore how astrocytes contribute in transporting K+ out from high-concentration regions via a mechanism known as spatial buffering, which involves local uptake from high concentration regions, intracellular transport, and release of K+ in regions with lower ECS concentrations.
Model Type: Neuron or other electrically excitable cell; Glia; Extracellular
Cell Type(s): Astrocyte
Currents: I K,leak; Na/K pump; I Cl, leak; I Na, leak
Model Concept(s): Methods; Potassium buffering
Simulation Environment: MATLAB
Implementer(s): Halnes, Geir [geir.halnes at nmbu.no]
References:
Halnes G, Ostby I, Pettersen KH, Omholt SW, Einevoll GT. (2013). Electrodiffusive model for astrocytic and neuronal ion concentration dynamics. PLoS computational biology. 9 [PubMed]