There is a copious amount of glutamate in mammalian cells.
Glutamate is necessary for excitatory signaling between neurons.
The release must be highly organized, due to the large amounts of glutamate at the synaptic cleft, and the fact that it is released at high speeds.
This mechanism of release at the synaptic cleft is partially controlled through the active transport of glutamate out of astrocytes by system Xc-.
This release also has a physiological role in the regulation of glutamate metabotropic receptors and control of other neurotransmitters.

It has been demonstrated that, in the embryonary retina, Xc- exchanger is responsible for 50% of total glutamate uptake, representing a Sodium-Independent system within this tissue.
The high activity of Xc- in the retina is correlated to a neuroprotective role, once it can take up excessive extracellular glutamate and provide precursors for the synthesis of Glutathione.
There is a copious amount of glutamate in mammalian cells. Glutamate is necessary for excitatory signaling between neurons. The release must be highly organized, due to the large amounts of glutamate at the synaptic cleft, and the fact that it is released at high speeds. This mechanism of release at the synaptic cleft is partially controlled through the active transport of glutamate out of astrocytes by system Xc-. This release also has a physiological role in the regulation of glutamate metabotropic receptors and control of other neurotransmitters.
It has been demonstrated that, in the embryonary retina, Xc- exchanger is responsible for 50% of total glutamate uptake, representing a Sodium-Independent system within this tissue. The high activity of Xc- in the retina is correlated to a neuroprotective role, once it can take up excessive extracellular glutamate and provide precursors for the synthesis of Glutathione.
Cystine/glutamate transporter