Role of nitric oxide in a progressive neurodegeneration model of Parkinson's disease in the rat.

This study was undertaken to investigate the nitric oxide synthase (NOS) activity in the striatum following 6-hydroxydopamine (6-OHDA) induced neurodegeneration in rats. Constitutive NOS (cNOS) activity remained unaltered at 3, 7 and 14 days after lesion, while a 43% and 45% decrease was observed at 30 and 50 days, respectively. Inducible NOS (iNOS) activity was detected only on the 3rd day after lesion and not in subsequent days or the control striatum. N(G)-nitro-L-arginine methyl ester (L-NAME) pretreatment blocked the amphetamine-induced rotations and inhibited the iNOS activity at the 3rd day after the 6-OHDA injection. L-NAME pretreatment also significantly restored the striatal dopamine (DA), dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) levels in 6-OHDA treated rats. Thus a possible role of nitric oxide in 6-OHDA induced neurodegeneration is suggested.