Astrocyte Heterogeneity or Homogeneity?

  • Harold K. Kimelberg

The history of the morphology and electrophysiology of the neuroglia, which was the historical term used for what are now termed astroglia, is briefly reviewed. The interpretation of these data around 1970 was that astroglia in situ represented a homogeneous electrophysiological phenotype with a major function, based on this, in maintaining a constant extracellular concentration of potassium ions ([K+]o). It was soon found that astroglia in situ played a major role in the uptake and inactivation of the synaptically released amino acid transmitters glutamate and γ-aminobutyric acid. Subsequent studies in isolated systems, such as primary astrocyte cultures, greatly expanded this view to a more protean cell, with much wider properties in terms of transmitter uptake systems and release, a variety of voltage-dependent ion channels and varying membrane potentials and electrophysiological behaviour, and receptors for a large number of neurotransmitters. Thus, it seemed quite reasonable that...


Glial Fibrillary Acidic Protein Glutamine Synthetase Stratum Radiatum Bergmann Glia Excitatory Amino Acid Transporter 
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.



Membrane capacitance


Central nervous system


Excitatory amino acid


Reversal potential


Glial fibrillary acidic protein


Glutamine synthetase




Total charge


Electrode access resistance


Membrane resistance


Total resistance


Voltage drop across R a


Clamp (command) potential


Total voltage drop


Extracellular concentration of potassium ions


Intracellular concentration of potassium ions



I thank Drs. Gary Schools and Min Zhou for discussions and reading the manuscript and for supplying some of the figures.


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© Springer Science+Business Media, LLC 2009

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  • Harold K. Kimelberg

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