Effects of resveratrol on the levels of ATP, 5-HT and GAP-43 in the hippocampus of mice exposed to chronic unpredictable mild stress

Growing evidence suggested that energy deficiency might be involved in the pathophysiological mechanism of depression. Energy deficiency, mainly results from mitochondrial damage, can lead to the dysfunction of synaptic neurotransmission, and further cause depressive-like behavior. The antidepressant effect of resveratrol had been widely demonstrated in previous studies; however, the underlying mechanism remains poorly understood. The present study aimed to investigate whether the antidepressant effects of resveratrol involved in the energy levels and neurotransmission in the hippocampus. We found that resveratrol and fluoxetine significantly attenuated depressive-like behaviors induced by chronic unpredictable mild stress (CUMS), which evidenced by the increased sucrose preference and the reduced immobility time in a forced swimming test. In addition, resveratrol increased hippocampal ATP levels, decreased Na+-K+-ATPase and pyruvate levels, and upregulated the levels of mitochondrial DNA (mtDNA), mRNA expression of sirtuin (SIRT)1 and peroxisome proliferator-activated receptor γ coactivator (PGC)1α. Furthermore, resveratrol and fluoxetine increased serotonin (5-HT) levels and downregulated the mRNA expression of 5-HT transporter (SERT) in the hippocampus. The decreased protein expression of growth-associated protein (GAP)-43 induced by CUMS was also ameliorated by resveratrol and fluoxetine. These findings demonstrated the antidepressant effects of resveratrol and suggested that resveratrol was able to promote mitochondrial biogenesis, enhance ATP and 5-HT levels, as well as upregulate GAP-43 expression in the hippocampus.