Lesion of the nigrostriatal neurons by 6-hydroxydopamine induces changes in rat brain glutathione-S-transferase

Wistar rats were lesioned into the nigrostriatal pathway with 6-OHDA. The D-amphetamine-induced circling behavior test was performed to evaluate lesion efficiency. Animals that showed more than 620 turns/90 min were named totally lesioned animals (TLA). The group of rats that performed less than 620 turns/90 min was named partially lesioned animals (PLA). The contents of DA and its catabolites in the striata of these groups, and in the same tissue of the untreated animals, were measured. Moreover, the striatal glutathione-S-transferase (GST) specific activity for all groups was tested, and the kinetics parameters for GST purified from the whole brain were evaluated from other three similar groups. The striatal DA depletion in TLA was greater than in PLA. Striatal GST activity showed a significant bilateral increase in PLA, whereas TLA exhibited only an ipsilateral augment. There were also differences between groups about the kinetic parameters of the purified brain enzyme. The possible role of GST on the interindividual lesion response difference was analyzed.