Nitric oxide synthase inhibition prevents acute QA-induced neurotoxicity

Abstract

In the present study we employed 7-NI, reportedly a selective inhibitor of neuronal nitric oxide synthase (NOS) and the non-specific potent NOS inhibitor I-NAME, to investigate the possible involvement of nitric oxide (NO) in quinolinic acid (QA)-induced striatal toxicity in the rat. QA was administered unilaterally into the striatum of adult Wistar rats in the single dose of 150 nmol/L. The second and third group were treated with 7-NI and QA and I-NAME and QA. The control group was treated with O.9% saline solution likewise. Nitrite levels were decreased in the ipsi- and contralateral striatum, forebrain cortex and hippocampus in the group treated with NOS inhibitors (7-NI, I-NAME) and QA compared to QA-treated animals. As 7-NI selectively inhibits the neuronal form of NOS, this study suggests that NO produced from a neuronal and not an epithelial source may contribute to neuronal damage in this model.