Abstract
Excitatory amino acid transporters (EAATs) encompass a class of five transporters with distinct expression in neurons and glia of the central nervous system (CNS). EAATs are mainly recognized for their role in uptake of the amino acid glutamate, the major excitatory neurotransmitter. EAATs-mediated clearance of glutamate released by neurons is vital to maintain proper glutamatergic signalling and to prevent toxic accumulation of this amino acid in the extracellular space. In addition, some EAATs also act as chloride channels or mediate the uptake of cysteine, required to produce the reactive oxygen speciesscavenger glutathione. Given their central role in glutamate homeostasis in the brain, as well as their additional activities, it comes as no surprise that EAAT dysfunctions have been implicated in numerous acute or chronic diseases of the CNS, including ischemic stroke and epilepsy, cerebellar ataxias, amyotrophic lateral sclerosis, Alzheimer’s disease and Huntington’s disease. Here we review the studies in cellular and animal models, as well as in humans that highlight the roles of EAATs in the pathogenesis of these devastating disorders. We also discuss the mechanisms regulating EAATs expression and intracellular trafficking and new exciting possibilities to modulate EAATs and to provide neuroprotection in course of pathologies affecting the CNS.
Highlights
The amino acid glutamate is the major excitatory neurotransmitter in the central nervous system (CNS)
Chloride channel activity emerges as a main physiological activity of EAAT4 and EAAT5
Import of cysteine into neurons to ensure glutathione synthesis for oxidative stress response appears to be a crucial role for EAAT3
Summary
The amino acid glutamate is the major excitatory neurotransmitter in the central nervous system (CNS) It is required for essential brain functions, such as learning and memory [1,2]. Since glutamate released by neurons is generally not metabolized in the extracellular space, the maintenance of normal glutamatergic neurotransmission and the prevention of glutamate-induced toxicity depends on active glutamate uptake into glial cells and neurons. It had been known since 1970s that a high affinity glutamate uptake system existed in the mammalian brain [4]. Cell Type and Subcellular Localization cerebellum astrocytes (perisynaptic) whole brain whole brain astrocytes (perisynaptic); axon terminals (presynaptic) neurons (postsynaptic, cell soma and dendrites) cerebellum neurons (postsynaptic, dendritic spines) retina neurons (presynaptic)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
