The Durk Pearson & Sandy Shaw®
Life Extension NewsTM
Volume 12 No.
3 • June 2009
Chronic Stress: Curcumin Protection in Chronically Stressed Rats
Who isn’t under a lot of stress these days? If you are, it is good to know that the major turmeric constituent curcumin provided major protection in chronically stressed rats, including reversing impaired hippocampal neurogenesis and up-regulating brain-derived neurotrophic factor (BDNF) expression and serotonin (5HT) receptor 1A mRNA.
The researchers subjected rats to chronic unpredictable stress (shaker stress, cold swim, restraint, tail pinch, water deprivation, and foot shock) once per day for various periods of time between 8 am and 12 am. Meanwhile, during the stressor period, rats were given chronic curcumin treatment (5, 10, and 20 mg/kg orally) or the antidepressant imipramine (10 mg/kg i.p.), or placebo. Curcumin at 10 or 20 mg/kg increased hippocampal neurogenesis in chronically stressed rats, similarly to the effect of imipramine treatment. The new cells were shown to mature and become neurons. Curcumin also significantly prevented the stress-induced decrease in 5-HT1A (serotonin 1A) receptors and BDNF (brain derived neurotrophic factor) protein levels in the hippocampal subfields, two molecules that function as part of hippocampal neurogenesis.
The negative effects of stress on motivation and cognition, including prolonged “learned helplessness” and increased corticosterone levels, have been shown to be reversed in animal models by fluoxetine (Prozac, a serotonin reuptake inhibitor antidepressant drug) and these effects are thought to be mediated by the serotonin receptor 1A. Brain-derived neurotrophic factor has been found to protect against the suppressed neurogenesis and increased neuronal death in the hippocampus that accompanies depression and post-traumatic stress disorder. The authors conclude: “These results raise the possibility that increased cell proliferation and neuronal populations may be a mechanism by which curcumin treatment overcomes the stress-induced behavioral abnormalities and hippocampal neuronal damage. Moreover, curcumin treatment, via up-regulation of 5-HT1A receptors and BDNF, may reverse or protect hippocampal neurons from further damage in response to chronic stress, which may underlie the therapeutic actions of curcumin.”
- Xu et al, Curcumin reverses impaired hippocampal neurogenesis and increases serotonin receptor 1A mRNA and brain-derived neurotrophic factor expression in chronically stressed rats. Brain Res 1162:9-18 (2007).