User:NeuroJoe/Oxytosis

Oxytosis, or oxidative glutamate toxicity, is a particular type of oxidative stress caused by exposure of neurons to glutamate. This happens most commonly in vivo due to stroke, which leads to the release of glutamate from dead and dying neurons. Oxytosis leads to a distinct mode of cell death separate from that caused by excitotoxicity.

When neurons are exposed to high levels of extracellular glutamate, the normal function of the cystine/glutamate antiporter xCT is inhibited. xCT is dependent upon a concentration gradient of both cystine and glutamate to function properly. Normally, glutamate is present in higher concentrations inside of the cell, and cystine is found in higher concentrations outside of the cell. The xCT antiporter exchanges one molecule of glutamate for one molecule of cystine across the plasma membrane. This import of cystine into the cell is critical to the redox balance of the cell, as cystine is a component of the main neuronal antioxidant glutathione. In fact, the transport function of xCT is the rate limiting step for glutathione production inside of neurons.