Stress-Relieving Gene

By Medical Discovery News

Oct. 20, 2012

One word serves as an instant conversation starter: stress. It’s inescapable, and comes from common experiences like deadlines and demanding bosses, a spouse who doesn’t understand and children who don’t obey, or bills to pay and endless chores to do. The added burden of a health crisis or relative’s death can cause stress to become acute. Though people throw the word around, unchecked stress takes a physiological and psychological toll.

Research shows chronic stress leads to mood disorders such as depression, which has enormous effects on the brain. It changes brain cell behavior and the structure of brain tissues. For example, the hippocampus, which is the brain’s memory center, can shrink in people with a history of depression. And neurons, which are cells that transmit brain signals, can slow down.

A new report further supports this causal link between stress and mood disorders. It shows chronic stress blocks a gene called neuritin that normally protects the brain from such disorders. A research team from Yale University studied how rats, which also possess the neuritin gene, responded to 35 days of stress induced by isolation, no food or play, and a change in their light and dark cycles.

As expected, the rats showed signs of depression. They lost interest in food, sweetened drinks, and didn’t swim when placed in water. An analysis showed these rats had significantly lower neuritin gene activity compared with rats in a control group. While some of the depressed rats were given antidepressants to recover, others were injected with a genetically engineered virus to increase neuritin gene activity. These rats recovered just as well as those given antidepressants, which suggests neuritin is effective at blocking stress and mood disorders.

To further prove neuritin can protect the brain from depression, researchers blocked the neuritin gene in healthy rats and saw them exhibit the same depressed states as rats exposed to chronic stress. The study supports past evidence that already began to link stress to the development and progression of mood disorders.

Past studies show a person suffering depression has lower levels of something called brain-derived growth neurotrophic factor (BDNF).  This protein factor is important in keeping neurons active and healthy. Other findings also suggested low neuritin gene activity diminished the coding of a protein that protects the brain’s ability to adapt to new experiences.

The findings will help scientists target a new method for treating the one in four Americans affected by mood disorders in any given year, according to the National Institute on Mental Health. Though antidepressants are currently available, only 30 percent of people taking them fully recover. Finding a new therapy that can promise better results can be life changing.

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