Role of hypothalamic-pituitary-adrenal-axis in affective disorders: Anti-depressant and anxiolytic activity of partial 5-HT1A agonist in adrenalectomised rats

Background: Depression is a neurological disorder characterized by sad mood, loss of pleasure, agitation and retardation. Though most relevant neuronal pathophysiology is characterized by decrease in monoamine namely; serotonin (5-HT), dopamine, noradrenaline level in central areas regulating mood and behavior, it inadequately explains the exact mechanism involved. Buspirone (BUS), a partial 5-HT _1A receptor agonist has shown promising anti-depressant and anxiolytic properties in various pre-clinical and clinical studies, but the molecular and cellular mechanisms are still unclear. Objective: The aim of this study was to investigate, in vivo, the role of hypothalamic-pituitary-adrenal (HPA) axis dysregulation in pathophysiology of depression-related disorders and the anti-depressant like activity of BUS. To simulate HPA axis dysregulation, rats were subjected to bilateral adrenalectomy (ADX). Materials and Methods: We have analyzed effect of BUS (10 mg/kg, i.p.) in ADX and sham rats using open field, sucrose consumption, elevated plus maze and hyper-emotionality tests. Results: In all animal models tested, ADX rats exhibited significant depressive and anxiogenic states while BUS was effective in reversing the psychological diseased condition developed. Conclusion: Taken together, these data showed a prominent role of HPA axis in depression and neuronal mechanism of BUS as anti-depressant and anxiolytic agent. Moreover, our findings suggest that BUS can be a better candidate for stress related depression and anxiety.