Researchers Create Animal Model Of Chronic Stress

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Researchers Create Animal Model Of Chronic Stress

http://medicalnewscenter.com/out/out.cgi?

http://www.sciencedaily.com/releases/2008/09/080903172156.htm

In an effort to better understand how chronic stress affects the

human body, researchers at the Yerkes National Primate Research

Center and the Department of Psychiatry and Behavioral Sciences,

Emory University, have created an animal model that shows how chronic

stress affects behavior, physiology and reproduction.

Developing the animal model better positions the researchers to

understand the neurohormonal causes of such stress and the body

reaction in order to develop more effective treatment options for

humans. The study is available in the current online edition of

Molecular Psychiatry.

According to lead researcher Mark , PhD, chief of the Division

of Psychobiology at Yerkes, " Chronic stress can lead to a number of

behavioral changes and physical health problems, including anxiety,

depression and infertility. "

Via the animal model, the researchers found corticotropin releasing

factor (CRF) is a key neurohormone involved in stress response.

explains, " CRF is located in several different brain regions,

serving different functions. Its release is important for our ability

to adapt to every day stressors and to maintain our physical and

emotional health. "

In response to stress, CRF levels rise; CRF levels decrease when the

stressor no longer is present. Chronic stress, however, increases the

length and volume of expression of CRF in areas of the brain

associated with fear and emotion, including the amygdala. Such

chronic stress changes the body's response, and the resulting

increased expression of CRF is thought to be the cause of such health-

related stress problems including anxiety, depression and infertility.

To study the importance of CRF, the research team used a viral vector

to increase the production of CRF in the amygdala of female rats.

" In our study, rats that continuously were exposed to CRF from this

area of the brain experienced anxious and depressive behavior,

decreased libido and disrupted ovarian cycles suggesting that

persistent release of CRF such as occurs in chronic stress clearly

affects multiple body systems, " says . " These behavioral

changes are similar to what we see in human females who are exposed

to stressors on a daily basis. "

Dr. and his research team next will attempt to learn more

about the negative effects of increased CRF by examining actual

molecular and cellular changes in specific brain areas targeted by

the neurohormone. Knowing how CRF affects the brain positions the

researchers to develop better treatment options.