Researchers isolate the chemicals in the brain that respond to stress.
Findings may possibly pinpoint why some subjects show symptoms of mental illness, and others don’t after exposure to stress.
"Talk to your doctor if you’re experiencing depression or PTSD"
Dr. Oliver Berton PhD., Assistant Professor of Psychiatry at the Perelman School of Medicine at the University of Pennsylvania, and a team of researchers wanted to better understand the brain’s response to stress.
When the body is under stress, the brain releases steroids called glucocorticoids to help regulate normal brain function. If too much glucocorticoid floods into the system, stress-response problems like depression and PTSD become a risk factor.
HDAC6 is a cellular protein that regulates the flow of glucocorticoids in the brain. Too much glucocorticoid in the brain causes depression and PTSD. Since glucocorticoids are necessary for normal function of metabolism, the immune system and hormones, the side effects of blocking glucocorticoids is physically dangerous. Researchers have also found that trying to prevent depression and PTSD is not as simple as blocking glucocorticoids anyway.
The discovery of HDAC6 as the regulator of glucocorticoids will change scientific outlook when it comes to developing anti-depressants for depression and PTSD.
Rather than looking at ways to alter the flow of glucocorticoids, which is risky, now scientists can look at how HDAC6 adapts to stress conditions.
If HDAC6 can be altered so that HDAC6 is responsible for adjusting glucocorticoid flow, then normal brain function can continue uninterrupted, while depression and PTSD are kept at bay.
In Dr. Berton’s experiments they used aggressive mice to intimidate normal mice to create a stress response in the normal mice's brains. Some mice developed symptoms consistent with PTSD, while others remained unaffected. The difference in the brain functions of the mice that were bullied by the aggressive mice had to do with the presence of HDAC6.
Less HDAC6 in the brain was the consistent factor in the group of mice that were unshaken by the bullying and did not show signs of depression or PTSD.
This new understanding of the way the stress response works in the brain could lay the groundwork for new discoveries and developments in anti-depressants used to treat stress-related disorders.
This study was published in The Journal of Neuroscience, March 28, 2012. Funding for this study came from grants provided by the National Institute of Mental Health and the International Mental Health Research Organization and the National Alliance for Research on Schizophrenia and Depression.
No conflicts of interest were reported or found.