Stress: The Negative Modulator of NGF

Abstract

Depression is associated with deficiencies in mono-aminergic transmitters and possibly neurotrophins. Stress-induced helplessness in rodents constitutes a well defined model to investigate neurobiological mechanisms of depression and to test the efficacy of antidepressant drugs. Neurotrophins like Nerve Growth Factor (NGF) have been shown to be involved in neurobiological changes due to physiological and pathological reactions to stress. In this study, we investigated NGF protein levels in the hippocampus in rat brain treated with an established model of learned helplessness and compared with untreated controls. NGF protein levels were significantly decreased in the hippocampus of chronically stressed rats than normal control. This decrease of hippocampal NGF constitutes the most striking correlate of neurobiological changes in this stress-induced behavioral model of depression.