Regulation of Synaptic Transmission by Ambient Extracellular Glutamate

Many neuroscientists assume that ambient extracellular glutamate concentrations in the nervous system are biologically negligible under nonpathological conditions. This assumption is false. Hundreds of studies over several decades suggest that ambient extracellular glutamate levels in the intact mam...

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Bibliographic Details
Published in:The Neuroscientist (Baltimore, Md.) Md.), 2008-04, Vol.14 (2), p.171-181
Main Authors: Featherstone, David E., Shippy, Scott A.
Format: Article
Language:English
Subjects:
Animals
Brain - metabolism
Brain - physiology
Extracellular Fluid - metabolism
Glutamate
Glutamic Acid - metabolism
Glutamic Acid - pharmacology
Nervous system
Neural transmission
Physiological aspects
Synaptic Transmission - drug effects
Synaptic Transmission - physiology
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Summary:Many neuroscientists assume that ambient extracellular glutamate concentrations in the nervous system are biologically negligible under nonpathological conditions. This assumption is false. Hundreds of studies over several decades suggest that ambient extracellular glutamate levels in the intact mammalian brain are ~0.5 to ~5 µM. This has important implications. Glutamate receptors are desensitized by glutamate concentrations significantly lower than needed for receptor activation; 0.5 to 5 µM of glutamate is high enough to cause constitutive desensitization of most glutamate receptors. Therefore, most glutamate receptors in vivo may be constitutively desensitized, and ambient extracellular glutamate and receptor desensitization may be potent but generally unrecognized regulators of synaptic transmission. Unfortunately, the mechanisms regulating ambient extracellular glutamate and glutamate receptor desensitization remain poorly understood and understudied. NEUROSCIENTIST 14(2):171—181, 2008. DOI: 10.1177/1073858407308518
ISSN:1073-8584
1089-4098
DOI:10.1177/1073858407308518