STUDIES ON BEHAVIORAL, BIOCHEMICAL, IMMUNOHISTOCHEMICAL AND QUANTIFICATION OF DOPAMINE AND ITS METABOLITES IN THE STRIATUM OF 6-HYDROXY DOPAMINE INDUCED PARKINSONISM IN RATS - ATTENUATION BY BACOSIDE-A, A MAJOR PHYTOCONSTITUENT OF BACOPA MONNIERA

摘要

Bacoside-A, a major constituent isolated from Bacopa monniera is held in high repute as a potent nerve tonic. Rats were pretreated with Bacoside - A (10mg/kg and 20mg/kg body weight) for 21 days. A Parkinsonian model in rats was developed by giving 6-hydroxy dopamine (12μg/2μl in 0.1% ascorbic acid- saline) in the right striatum on 22ndday. A significant protection on lipid peroxidation, glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase and catalase was observed in the striatum of lesioned group animals pretreated with 10 mg/kg body weight of Bacoside-A for 21 days as compared to lesion group animals. We tested the behavioral response at different time points after injection of 6-hydroxy dopamine to evaluate the onset and progression of behavioral abnormalities. Also quantification of dopamine and its metabolites, DOPAC and HVA was done using HPLC coupled with electrochemical detector. The results showed a reduction in the levels of dopamine and its metabolites, increase in the locomotor activity, increase in "depression"-like behavior and a marked change in the social behavior in the 6 - hydroxy dopamine induced group whereas learning and memory abilities were not affected. Finally, all of these results were exhibited by an increase in the density of TH-IR fibers in the ipsilateral substantia nigra of the lesioned group following treatment with Bacoside-A. This study indicates that Bacoside-A, an active compound from Bacopa monniera, is helpful in attenuating the changes caused by 6-hydroxy dopamine induced lesions and has therapeutic potential in fighting against Parkinson's