Role of astrocytes in the clearance of excess extracellular potassium

@article{Walz2000RoleOA,
  title={Role of astrocytes in the clearance of excess extracellular potassium},
  author={Wolfgang Walz},
  journal={Neurochemistry International},
  year={2000},
  volume={36},
  pages={291-300}
}
  • W. Walz
  • Published 1 April 2000
  • Biology
  • Neurochemistry International
View on Elsevier
doi.org
423 Citations
Highly Influential Citations
26
Background Citations
233
Methods Citations
9
Results Citations
5

423 Citations

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Citation Type

Chapter 8 The Impact of Astrocytes in the Clearance of Neurotransmitters by Uptake and Inactivation
The Neuroglial Potassium Cycle during Neurotransmission: Role of Kir4.1 Channels
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It is demonstrated that astroglial Kir4.1 channels are sufficient to account for the slow membrane depolarization of hippocampal astrocytes and crucially contribute to extracellular potassium clearance during basal and high activity.
Chapter 7 – Potassium Channels
Interstitial ions: A key regulator of state-dependent neural activity?
Potassium buffering in the neurovascular unit: models and sensitivity analysis.
The astrocyte biochemistry.
Glial K+ Clearance and Cell Swelling: Key Roles for Cotransporters and Pumps
TLDR
The glial cell swelling associated with K+ clearance is prevented under conditions that block the activity of the Na+/K+/Cl− cotransporter, which serves as a K+-dependent molecular water pump under conditions of increased extracellular K+ load.
Chloride/anion channels in glial cell membranes
TLDR
Of greatest interest are two phenomena discovered in situ: The ClC‐2 channel is only found in astrocytic endfeet near blood capillaries adjacent to neuronal GABAA receptors, and in the supraoptic nucleus of the hypothalamus, there is an osmosensitive astroCytic taurine release.
Dynamics of ion fluxes between neurons, astrocytes and the extracellular space during neurotransmission
TLDR
The predictions of the tri-compartment model based on mass-action kinetics equations are extended by assessing the selective contribution of the astroglial and neuronal Na/K ATPase, or volume of the extracellular space on potassium dynamics, and their implications for neuronal information processing in the healthy and diseased brain are discussed.
Sodium dynamics in neurons and astrocytes under epileptifom conditions
TLDR
The results show that large and long-lasting Na transients occur during synchronized activity of the endogenous circuitry and suggest that metabolic support of neurons during enhanced activity, provided by astrocytes, is necessary to maintain neuronal Na homeostasis.
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References

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TLDR
Astrocytes in the gliotic stratum radiatum of the hippocampal slice have the capacity to limit increases in extracellular K+ that are produced by hyperactive surviving hippocampal neurons by passive mechanisms and hence independently of blood and oxygen supply.
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  • Biology
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The mechanism of K+ uptake in NG cells is by passive KCl and water influx, which causes cell swelling, and it is concluded that chloride is passively distributed across the NG cell membrane.
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Numerical calculations show that the principal data on K+ dynamics from various laboratories can be accounted for with simple assumptions about spatial buffer action and uptake, and much of the data is inconsistent with extracellular diffusion being the main mechanism for K+ flux through brain tissue.
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It is concluded that changes in the intracellular Cl- concentration alter the outward K+ conductances of astrocytes, which will have important consequences for the progression of spreading depression through brain tissue and forAstrocytic swelling in pathological situations.
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The results suggest that volume changes in cultured glial cells during exposure to high K+ should be taken into consideration since they disguise K+ accumulation when only ion activity is measured.
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TLDR
Analysis of neural activity-dependent fluctuations in K+, H+, and ECS dimensions in the developing RON has revealed major changes during the first two to three postnatal weeks, leading to the hypothesis that ECS shrinkage depends upon electrolyte and water transport into glial cells with subsequent swelling.
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TLDR
Evidence is provided for a long-lasting modification in the [Ca2+]i oscillatory response induced by glutamate in astrocytes that demonstrates that in the central nervous system cellular memory is not a unique feature of neurons.
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