The almost linear current-voltage relationship of most glial membranes results from multiple non-linear potassium leaky-pore or background conductances. The corresponding channel types develop and deregulate independently, some of them asymmetrically – producing non-monotonic I-V curves. The consequences of those alterations on whole-cell voltage responses have not been explored. We developed a minimal ordinary differential equation model of voltage dynamics incorporating detailed models of the different potassium currents based on electrophysiological recordings. Parametrically inducing some of the reported changes in rectification of glial Kir currents resulted in instability of the nominal resting membrane potential and the appearance of a second, much more depolarized resting state. If prolonged glial depolarizations prove plausible such bistability would change the present understanding of glial Vm dynamics.
Model Type: Glia
Region(s) or Organism(s): Hippocampus
Cell Type(s): Astrocyte
Currents: Kir; I Potassium
Model Concept(s): Bifurcation; Detailed Neuronal Models
Simulation Environment: XPPAUT
Implementer(s): Janjic, Predrag; Solev, Dimitar
References:
Janjic P, Solev D, Kocarev L. (2023). Non-trivial dynamics in a model of glial membrane voltage driven by open potassium pores Biophysical journal. 122 [PubMed]