Parkinson's disease (PD) a neurodegenerative disorder for which no preventive or long-term effective treatment strategies are available. Epidemiologic studies have failed to identify specific environmental, dietary or lifestyle risk factors for PD. However, oxidative stress in the SN is the most broadly accepted hypothesis for the etiopathology of PD. The Symptoms do not appear until there is a decline of striatal dopamine levels by 80% making it difficult to have early therapeutic interventions. Thus, the present experiment was designed to track down the sequential changes starting from the initiation of motor dysfunction and associated biochemical abnormality in rotenone based PD model. The study also evaluated the neuroprotective efficacy of vitamin E. Rats were treated with rotenone 2 mg/kg b.wt (s.c.) for 35 days. The level of dopamine decreased by 70~80% which was in turn reflected by marked deterioration in motor function such as (Total locomotor activity and catalepsy). Along with these the level of GSH and SOD declined significantly which was associated with elevated lipid peroxidation levels as much as by 60%.Vitamin E co-administration at a dose of 100 I.U/kg b.wt (i.m.) ameliorated rotenone induced changes in motor functions i.e Total locomotor activity and Catalepsy at the end of 5^th week. Further, vitamin E supplementation significantly decreased lipid peroxidation and improved associated biochemical parameters i.e SOD and GSH level. Most interestingly the changes appeared as early as 3^rd week suggesting that supplementation of vitamin E right at the beginning should be neuroprotective in PD.

Keywords: Parkinson's disease, substantia nigra, oxidative stress, pars compacta, rotenone, catalepsy