Put a mouse or a rat under stress and what does it do? It stops eating. Humans should be so lucky. When people suffer nontraumatic stress they often head for the refrigerator, producing unhealthy extra pounds.

When Syrian hamsters, which are normally solitary, are placed in a group-living situation, they also gain weight. So scientists at the Center for Behavioral Neuroscience at Georgia State University are using hamsters as a model for human stress-induced obesity. They want to begin unraveling the complex factors that lead people to eat when under stress and hope that the information can eventually be used to block appetites under this common scenario.

The study, "Social defeat increases food intake, body mass, and adiposity in Syrian hamsters," by Michelle T. Foster, Matia B. Solomon, Kim L. Huhman and Timothy J. Bartness, Georgia State University, Atlanta, appears in the recent issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology published by The American Physiological Society.

Hamsters similar to humans
In the study, the researchers look at nontraumatic stress -- the stress we experience in everyday life, such as getting stuck in traffic or trying to complete a major project at work. It is distinct from traumatic stress, such as suffering the death of a loved one. Traumatic stress typically dulls the human appetite, said Bartness, the study's senior researcher and an authority on obesity.

In the U.S., where food is plentiful and relatively cheap, overeating can be difficult to control. Stress-related overeating is more difficult to control than the overeating that people do just because food tastes good and is available, Bartness said. If scientists could learn how to reduce the urge to eat in the face of stress, it could improve the health of a lot of people. And that was the point of this study.

The researchers used Syrian hamsters, the kind commonly found in pet stores. They set up a situation in which subordinate hamsters would suffer a "social defeat" at the hands of a dominant hamster. The researchers wanted to see if the defeated hamsters would eat more and gain weight under the stress, just like a human. Mice and rats eat less and lose weight when subjected to a similar stress, making them a poor subject for human stress-induced obesity research.



Posted by: Kelly    Source