Electrodiffusive model for astrocytic and neuronal ion concentration dynamics.

The cable equation is a proper framework for modeling electrical neural signalling that takes place at a timescale at which the ionic concentrations vary little. However, in neural tissue there are also key dynamic processes that occur at longer timescales. For example, endured periods of intense ne...

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Autores principales:	Geir Halnes, Ivar Ostby, Klas H Pettersen, Stig W Omholt, Gaute T Einevoll
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2013
Materias:	Biology (General) QH301-705.5
Acceso en línea:	https://doaj.org/article/718a6943274544e983bc74d51ede812a
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spelling	oai:doaj.org-article:718a6943274544e983bc74d51ede812a2021-11-18T05:53:16ZElectrodiffusive model for astrocytic and neuronal ion concentration dynamics.1553-734X1553-735810.1371/journal.pcbi.1003386https://doaj.org/article/718a6943274544e983bc74d51ede812a2013-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/24367247/pdf/?tool=EBIhttps://doaj.org/toc/1553-734Xhttps://doaj.org/toc/1553-7358The cable equation is a proper framework for modeling electrical neural signalling that takes place at a timescale at which the ionic concentrations vary little. However, in neural tissue there are also key dynamic processes that occur at longer timescales. For example, endured periods of intense neural signaling may cause the local extracellular K(+)-concentration to increase by several millimolars. The clearance of this excess K(+) depends partly on diffusion in the extracellular space, partly on local uptake by astrocytes, and partly on intracellular transport (spatial buffering) within astrocytes. These processes, that take place at the time scale of seconds, demand a mathematical description able to account for the spatiotemporal variations in ion concentrations as well as the subsequent effects of these variations on the membrane potential. Here, we present a general electrodiffusive formalism for modeling of ion concentration dynamics in a one-dimensional geometry, including both the intra- and extracellular domains. Based on the Nernst-Planck equations, this formalism ensures that the membrane potential and ion concentrations are in consistency, it ensures global particle/charge conservation and it accounts for diffusion and concentration dependent variations in resistivity. We apply the formalism to a model of astrocytes exchanging ions with the extracellular space. The simulations show that K(+)-removal from high-concentration regions is driven by a local depolarization of the astrocyte membrane, which concertedly (i) increases the local astrocytic uptake of K(+), (ii) suppresses extracellular transport of K(+), (iii) increases axial transport of K(+) within astrocytes, and (iv) facilitates astrocytic relase of K(+) in regions where the extracellular concentration is low. Together, these mechanisms seem to provide a robust regulatory scheme for shielding the extracellular space from excess K(+).Geir HalnesIvar OstbyKlas H PettersenStig W OmholtGaute T EinevollPublic Library of Science (PLoS)articleBiology (General)QH301-705.5ENPLoS Computational Biology, Vol 9, Iss 12, p e1003386 (2013)
institution	DOAJ
collection	DOAJ
language	EN
topic	Biology (General) QH301-705.5
spellingShingle	Biology (General) QH301-705.5 Geir Halnes Ivar Ostby Klas H Pettersen Stig W Omholt Gaute T Einevoll Electrodiffusive model for astrocytic and neuronal ion concentration dynamics.
description	The cable equation is a proper framework for modeling electrical neural signalling that takes place at a timescale at which the ionic concentrations vary little. However, in neural tissue there are also key dynamic processes that occur at longer timescales. For example, endured periods of intense neural signaling may cause the local extracellular K(+)-concentration to increase by several millimolars. The clearance of this excess K(+) depends partly on diffusion in the extracellular space, partly on local uptake by astrocytes, and partly on intracellular transport (spatial buffering) within astrocytes. These processes, that take place at the time scale of seconds, demand a mathematical description able to account for the spatiotemporal variations in ion concentrations as well as the subsequent effects of these variations on the membrane potential. Here, we present a general electrodiffusive formalism for modeling of ion concentration dynamics in a one-dimensional geometry, including both the intra- and extracellular domains. Based on the Nernst-Planck equations, this formalism ensures that the membrane potential and ion concentrations are in consistency, it ensures global particle/charge conservation and it accounts for diffusion and concentration dependent variations in resistivity. We apply the formalism to a model of astrocytes exchanging ions with the extracellular space. The simulations show that K(+)-removal from high-concentration regions is driven by a local depolarization of the astrocyte membrane, which concertedly (i) increases the local astrocytic uptake of K(+), (ii) suppresses extracellular transport of K(+), (iii) increases axial transport of K(+) within astrocytes, and (iv) facilitates astrocytic relase of K(+) in regions where the extracellular concentration is low. Together, these mechanisms seem to provide a robust regulatory scheme for shielding the extracellular space from excess K(+).
format	article
author	Geir Halnes Ivar Ostby Klas H Pettersen Stig W Omholt Gaute T Einevoll
author_facet	Geir Halnes Ivar Ostby Klas H Pettersen Stig W Omholt Gaute T Einevoll
author_sort	Geir Halnes
title	Electrodiffusive model for astrocytic and neuronal ion concentration dynamics.
title_short	Electrodiffusive model for astrocytic and neuronal ion concentration dynamics.
title_full	Electrodiffusive model for astrocytic and neuronal ion concentration dynamics.
title_fullStr	Electrodiffusive model for astrocytic and neuronal ion concentration dynamics.
title_full_unstemmed	Electrodiffusive model for astrocytic and neuronal ion concentration dynamics.
title_sort	electrodiffusive model for astrocytic and neuronal ion concentration dynamics.
publisher	Public Library of Science (PLoS)
publishDate	2013
url	https://doaj.org/article/718a6943274544e983bc74d51ede812a
work_keys_str_mv	AT geirhalnes electrodiffusivemodelforastrocyticandneuronalionconcentrationdynamics AT ivarostby electrodiffusivemodelforastrocyticandneuronalionconcentrationdynamics AT klashpettersen electrodiffusivemodelforastrocyticandneuronalionconcentrationdynamics AT stigwomholt electrodiffusivemodelforastrocyticandneuronalionconcentrationdynamics AT gauteteinevoll electrodiffusivemodelforastrocyticandneuronalionconcentrationdynamics
_version_	1718424672560742400

Electrodiffusive model for astrocytic and neuronal ion concentration dynamics.

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