Selective pharmacological changes of regional ascorbic acid metabolism in the brain

A growing body of evidence indicates for ascorbate a very important role in CNS functioning, rather than just fulfilling the relatively passive roles of general reducing agent and enzymatic cofactor. On-going modulation of synaptic events, locomotor activity, intermodulation with the consciousness state, are new fields of ascorbate activity. Several CNS drugs, according to their kind of activity, induce increase or decrease of extracellular brain ascorbate levels; moreover, they can, like d-amphetamine, activate the ascorbate transport system to CNS. Also regional brain ascorbate metabolism can be selectively activated by drugs. Activation of postsynaptic dopaminergic receptors increases ascorbate oxidation in striatum, but not in hypothalamus. Finally, the active transport of ascorbate to neural tissue and its efficient homeostatic system limit the ascorbate therapeutic potential on CNS.