Ascorbate regulation and its neuroprotective role in the brain

Ascorbic acid (vitamin C) occurs physiologically as the ascorbate anion:a w ater-soluble antioxidant that is found throughout the body. However, despit e the high, homeostatically regulated levers of brain ascorbate, its specif ic functions in the CNS are only beginning to be elucidated. Certainly it a cts as part of the intracellular antioxidant network, and as such is normal ly neuroprotective. There is also evidence that it acts as a neuromodulator . A possibly unique role it might have is as an antioxidant in the brain ex tracellular microenvironment, where its concentration is modulated by gluta mate-ascorbate heteroexchange at glutamate uptake sites. Ongoing studies of ascorbate and glutamate transporters should lead to rapid progress in unde rstanding ascorbate regulation and function.