Vitamin C is an antioxidant vitamin that accumulates in the brain from the blood supply and is maintained at relatively high concentrations under widely varying conditions. Although neurons are known to use this vitamin in many different chemical and enzymatic reactions, only recently has there been sufficient evidence to suggest a role for vitamin C in interneuronal communication.
Evidence from receptor binding studies suggests that ascorbate alters dopamine receptors either as an allosteric inhibitor or as an inducer of iron-dependent lipid peroxidation. However, the applicability of these studies to dopamine receptor function remains to be confirmed in light of reports that ascorbate can protect against lipid peroxidation in vivo.
Ascorbate also appears to modulate glutamatergic transmission in the neostriatum. Indeed, ascorbate may indirectly counteract the action of dopamine by facilitating glutamate release, although the nature of the neostriatal dopaminergic-glutamatergic interaction is far from clear.
