Excitatory amino acid transporters EAATs

Fig. 3. Synaptic localization of the mGluRs. The predominant localizations of the seven mGluR subtypes expressed in the CNS. The typical localizations of iGluRs and excitatory amino acid transporters (EAATs) are given, and the regulation of Glu release, iGluR signaling and ion channel activities mediated by the mGluRs is shown.

Excitatory amino acid transporters (EAATs) are the primary regulators of extracellular glutamate concentrations in the CNS. Glutamate clearance (and consequently glutamate concentration and diffusion in the extracellular space) is associated with the degree of astrocytic coverage of its neurons (Oliet et al. 

Glutamate transporters, also referred to as excitatory amino acid transporters (EAATs), clear synaptically released glutamate from the extracellular space, thus ensuring the precise control of excitatory synaptic transmission. In addition, excessive extracellular concentrations of glutamate can be neurotoxic and the efficient removal of glutamate limits pathological conditions associated with excitotoxic cell death. The transport cycle and stoichiometry of EAATs, of which hve mammalian isoforms have been characterised, is presented in Figure 9.13. 

FIGURE 9.13 Transport cycle and stoichiometry of excitatory amino acid transporters (EAATs). Simplified state diagram of the EAAT transport cycle. After glutamate and coupled ions (step 1) bind to the transporter (T), they are translocated (step 2) and released into the cell cytosol (step 3). Next binds from the intracellular side (step 4) and reorients the substrate-fiEe transporter (step 5). is released outside the cell (step 6). (From Jiang Amara, 2011. Reproduced with permission from Elsevier.)... 

EAAT excitatory amino acid transporter GLUT glucose transporter guanosine 5 -monophosphate... 

Chretien F., Le Pavec G., Vallat-Decouvelaere A. V., Delisle M. B., Uro-Coste E., Ironside J. W., Gambetti P., Parchi P., Creminon C., Dormont D., Mikol J., Gray F., and Gras G. (2004). Expression of excitatory amino acid transporter-1 (EAAT-1) in brain macrophages and microglia of patients with prion diseases. J. Neuropathol. Exp. Neurol. 63 1058-1071. 

TTie actual meanings of the acronyms (GLAST, glutamate-aspartate transporter GLT. glutamate transporter EAAC. excitatory amino acid carrier EAAT. excitatory amino acid transporter) are not important, as they do not reflect functional differences among the transporters. 

EAAT excitatory amino acid transporter (synonym to glutamate transporter)... 

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