Astrocytes in Control of the Biophysical Properties of Extracellular Space

  • Lydia Vargova
  • Eva Sykova

9.1 Extracellular Space (ECS) and Extrasynaptic Transmission

The extracellular space of the central nervous system (CNS) represents the microenvironment of the cellular elements: neurons and glia. Its composition, chemical and biophysical properties are crucial for the proper functioning of neurons and signal transmission. The first estimates of ECS volume that appeared in the second half of the last century were based on electron microscopy. However, the true values were altered by conventional preparation procedures, leading to the erroneous conclusion that the ECS represents less than 5% of the total brain tissue volume (Villegas and Fernandez, 1966). Later, it was shown by a number of different techniques (electron microscopy that preserves the ECS, radiotracers and ion diffusion methods) that under physiological conditions the average ECS volume is about 15–25% of the total adult brain volume [for review see (Nicholson and Sykova, 1998)]. Not only the volume, but also the...


Experimental Autoimmune Encephalomyelitis Diffusion Barrier Regulatory Volume Decrease Extracellular Matrix Molecule Astrocytic Process 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



Extracellular volume fraction


Apparent diffusion coefficient


Apparent diffusion coefficient of water


α-Amino-3-hydroxy-5-metyl-isoxazol-4-propionic acid


Central nervous system


Chondroitin-sulphate proteoglycan


Diffusion coefficient


Day post wounding


Diffusion-weighted magnetic resonance imaging


Experimental autoimmune encephalomyelitis


Extracellular matrix


Extracellular space


γ-Aminobutyric acid


Glial fibrillary acidic protein


Intrinsic optical signals


Ion-selective microelectrode


Nonspecific cellular uptake


Extracellular concentration of potassium ions






Extracellular pH


Intracellular pH


Regulatory volume decrease








World Health Organization



The authors acknowledge the support of grants AV0Z50390512 from the Academy of Sciences of the Czech Republic and LC554 from the Ministry of Education, Youth and Sports of the Czech Republic.


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Authors and Affiliations

  • Lydia Vargova
  • Eva Sykova

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