Neuroscience
Role of Cholinergic and Dopaminergic Systems in the Amelioration of Stress Induced Deficits
My PhD project dealt with the effects of stress on brain functions and possible ways of reversing stress-induced deficits and yielded some interesting results. We evaluated the effects of treatment with dopaminergic and cholinergic agonists on restraint stress-induced hippocampal dependent behavioural deficits. Rats subjected to restraint stress followed by treatment with bromocriptine or oxotremorine for 10 days were trained in a radial arm maze task and their learning was evaluated. Stressed rats exhibited impairment in performance, where as stressed rats subjected to bromocriptine or oxotremorine treatment showed better performance. There was a restoration of AChE activity and dopamine levels in the hippocampus following oxotremorine and bromocriptine treatment, respectively. Further, both the drugs reversed the stress-induced decrease in the number of BrdU-immunoreactive cells in the dentate gyrus indicating restoration of cell proliferation.
To know more read the Neuroscience and Psychopharmacology papers.
If you would like to learn more about stress and neurogenesis, click on Adult Neurogenesis.
Testing herbal extracts (Euphorbia hirta) in stress-induced anxiety
Chronic stress is known to precipitate several affective disorders including depression and anxiety. Drugs of natural origin are known to possess several effects on the central nervous system and are emerging as promising alternative therapies. In this context, the hydroalcoholic extract of Euphorbia hirta (Eh) was evaluated for anxiolytic property in chronically stressed rats subjected to elevated plus maze (EPM) and open field test (OFT). Eh treatment showed marked anti-anxiety activity in chronic immobilization stress. In contrast, the forced swim stress-induced anxiety was only partially decreased by Eh. Co-treatment of rats with flumazenil, bicuculline or picrotoxin resulted in a significant reduction of anxiolytic effect of Eh indicating that its actions are mediated through GABAA receptor-benzodiazepine receptor-Cl- channel complex. Read the JNT paper.
Synaptic plasticity following stress and the effect of bromocriptine and oxotremorine
Since earlier studies suggested that chronic stress impairs learning and this is restored by either bromocriptine, we wanted to understand if any changes in hippocampal SC-CA1 LTP underlie these changes. We found that stress decreases hippocampal LTP, which was reversed by either bromocriptine or oxotremorine treatment. This project stimulated my interest in electrophysiology and provided initial training in recording field potentials.
Synaptic plasticity in the hippocampal mossy fibre-CA3 synapse
At Christophe Mulle's laboratory, I worked on synaptic plasticity in the hippocampal mossy fibre-CA3 synapse.
Drug Discovery at Biocon-Bristol-Myers Squibb Research Centre, Syngene International Ltd.
I was leading drug discovery programs in depression and fibrosis