Gene Expression of Tyrosine Hydroxylase and Glutamate Receptors GluR1 and NR1 in Striatal Neurons of Parkinsonian Rats and Modulatory Effect of Bacoside-A, A Principle Constituent of Bacopa Monniera Linn

Author(s): Shobana Chandrasekar

Abstract

Our previous studies have provided evidences that Bacoside-A can protect the brain from 6-hydroxy dopamine (6-OHDA) induced Parkinson’s disease in rats by means of behavioral, biochemical and immunohistochemical evidences. In the present study, the modulation of the gene expression of GluR1, an α-amino-3- hydroxy-5-methyl-4-isoxazole-propionate (AMPA) glutamate receptor and NR1, N-methyl-d-aspartate (NMDA) receptor in the striatum of the 6-OHDA lesioned rat. The reverse transcriptase-polymerase chain reactions (RT-PCRs) showed significant reduction in GluR1 mRNA expression but a significant increase of NR1 mRNA expression in the striatal tissues of the lesioned side which was brought back to normalcy by Bacoside-A treatment after 2 weeks. Impaired Mitochondrial Complex I activity and MTT assay in 6-OHDA induced rats was attenuated by Bacoside – A treatment. At the neurochemical level, the decreased level of BDNF in 6-OHDA induced rats was significantly increased by Bacoside-A treatment. There were no significant changes observed in GDNF and NT-3 levels. Elevated levels of TNF – α and IL-6 were found to be reduced after Bacoside-A treatment. Bacoside-A treatment significantly caused a marked upregulation of tyrosine hydroxylase (TH) -mRNA expression confirming the anti-parkinson's effect of Bacoside-A. Collectively, our findings provide valid evidence on the neuroprotective effect of Bacoside-A in rat brain, which shows the neuro-therapeutic potential in mitigating 6 - OHDA induced neuronal dysfunctions.