PROTECTION OF THE AGED SUBSTANTIA-NIGRA OF THE RAT AGAINST OXIDATIVE DAMAGE BY (-)-DEPRENYL

1 We have studied the effect of (-)-deprenyl on the oxidative damage t hat the rat substantia nigra suffers during aging. 2 (-)-Deprenyl (2 m g kg(-1), three times a week) administered for two months, beginning a t 22 months of age, produced a significant increase in tyrosine hydrox ylase (TH) activity (2.67+/-0.40 and 3.64+/-0.38 nmol mg(-1) protein h (-1) in untreated aged rats and treated aged rats respectively, P<0.05 ) and in TH amount (0.072+/-0.012 and 0.128+/-0.38 absorbance 405 nm i n untreated aged and treated aged rats respectively, P<0.05). 3 The pr oteins of aged rat substantia nigra showed a significant decrease of c arbonyl groups in treated animals compared with saline-injected contro l rats (136.2+/-21.8 and 71.5+/-13.2 c.p.m. mu g(-1) protein in untrea ted aged and treated aged rats respectively, P<0.05). 4 The carbonyl g roups measured in TH enzyme showed a statistically significant decreas e (42.3%) after (-)-deprenyl treatment (471.4+/-73.0 and 271.9+/-50.00 c.p.m. in untreated aged and treated aged rats respectively, P<0.001) . 5 All these results suggest that oxidative damage produced during ag ing is prevented by (-)-deprenyl treatment and could explain the effec t of this drug in Parkinson's disease (PD) and other degenerative dise ases such as Alzheimer's disease.