Investigations on light induced stress model and on the role of Phyllanthus amarus in attenuation of stress related depression with focus on 5HT2Am- RNA expression

BACKGROUND There is an increasing evidence that psychological stress and depression trigger changes in various biochemical parameters in animals and human subjects. Chronic stress in rats, and psychosocial stress in humans, is implicated in the pathophysiology of mood and anxiety disorders. PURPOSE The current study was been designed to investigate the behavioral, anatomical status of rat brain and expression of serotonin receptor (5HT2A) mRNA related to pathophysiology of stress after high light (HL) illumination and to evaluate the effect of Phyllanthus amarus (PA) over such stress induced changes in mid brain and prefrontal cortex region of rat brain. METHODS Bright light illumination was used to induce stress in wistar rats. Established methods were used to analyse biochemical and histopathological tests. RESULTS PA administration to HL stressed animals for 7 days prevented stress-induced oxidative damage, as evidenced by significant enhancement of key endogenous antioxidant defense components. HL stress also caused reduced activities of membrane bound enzymes in synaptic membrane along with reduced levels of lipid profile and glycoprotein in the midbrain region. Stress induced changes in the locomotor activity, time spent for exploring the center of the arena, frequency of rearing and grooming, and frequency of facing the corner of the arena, were altered on PA administration. CONCLUSION The findings suggest that the therapeutic efficacy of PA may be mediated, atleast partially, via reversal of oxidative damage. Further the study demonstrates the promising intervention by PA on the mRNA expression of 5HT 2A in the brain. These preliminary results pave the way for further validation of PA against stress.