Protective effect of histidine on MPP+-induced hydroxyl radical generation in rat striatum

Abstract

We investigated the efficacy of histidine on MPP+-induced hydroxyl radical (⋅OH) formation in extracellular fluid of rat striatum. Rats were anesthetized and sodium salicylate in Ringer's solution (0.5 nmol μl−1 min−1) was infused through a microdialysis probe to detect the generation of ⋅OH as reflected by the nonenzymatic formation of 2,3-dihydroxybenzoic acid (DHBA) in the striatum. MPP+ (5 mM) clearly produced an increase in ⋅OH formation. However, histidine (25 mM) reduced the ⋅OH formation by the action of MPP+. These results indicate that histidine protects MPP+-induced ⋅OH formation in rat striatum.