Oxygen radicals differentially affect Na+/Cl--dependent transporters

Incubation with the oxygen radical-generating enzyme, xanthine oxidase, dra matically reduced striatal dopamine transporter activity, but was unexpecte dly without effect on rat hippocampal norepinephrine uptake. To determine w hether environmental differences between the striatum and hippocampus contr ibuted to this lack of oxidative effect on norepinephrine transporters, syn aptosomal gamma-aminobutryic acid (GABA) uptake was assessed in both region s. Xanthine oxidase similarly decreased [H-3]GABA uptake in both the striat um and hippocampus, supporting the conclusion that environmental difference s did not account for the lack of effect on norepinephrine transport. These data suggest that norepinephrine transporters are less vulnerable than oth er Na+/Cl--dependent transporters to oxidative inactivation. (C) 1999 Elsev ier Science B.V. All rights reserved.