Within the retina, extracellular glutamate concentrations must be strictly regulated to facilitate neurotransmission. The outer retinal neurons respond to light stimulation with graded potentials, rather than action potentials; thus the concentration of glutamate in the synaptic cleft encodes the light signal. Furthermore, regulation of extracellular glutamate concentrations within the central nervous system is extremely important as over-stimulation of glutamate receptors causes neurotoxicity. High-affinity glutamate transporters (excitatory amino acid transporters, EAATs) located on neuronal and glial cell membranes are responsible for cellular glutamate sequestration and the balancing of extracellular concentration between the level required for physiological neurotransmission and the level that would lead to pathological excitotoxicity. The glial and neuronal high-affinity glutamate uptake systems allow the rapid removal of glutamate from the...
|Title of host publication
|Ocular Transporters In Ophthalmic Diseases And Drug Delivery
|Joyce Tombran-Tink, Colin J. Barnstable
|Place of Publication
|Number of pages
|Published - 2008