Stress Prompts Hamsters to Overeat: These rodents may hold the answer to battling human obesity
Pressures at work, conflicts in personal relationships, childcare demands and traffic snarls Ð many people deal with such day-to-day stress by overeating resulting in weight gain and obesity. Is there relief in sight?
CBN (Center for Behavioral Neuroscience in Atlanta, Ga.) researchers say Syrian hamsters may hold vital clues to curbing those unhealthy cravings.
Until now, rodents have not been useful as a model for human stress-induced obesity because the typical response of laboratory rats and mice to a wide range of stressors is to decrease food intake and body weight, but a CBN collaboration has found this isn't the case with Syrian hamsters.
In a study published in the May issue of the American Journal of Physiology. Regulatory, Integrative and Comparative Physiology,* GSU scientists Tim Bartness and Kim Huhman along with CBN graduate students, Michelle Foster and Matia Solomon, confirmed that not only do Syrian hamsters increase body and fat mass under social stress, but interestingly enough, most of the weight is gained in the abdominal area (visceral fat), making this species an ideal model for human stress-induced obesity.
The group conducted a series of resident-intruder sessions where they placed an 11-week-old hamster (subordinate intruder) in a cage with an older hamster (dominant resident). After several seven-minute trial periods, a clear dominance hierarchy developed between the hamsters where one of the animals showed subordinance or "defeat" in the presence of the other.
The results of the study showed that social stress produced by subjecting Syrian hamsters to defeat reliably triggered increased food intake and body and lipid mass. Therefore, this form of social defeat, a natural stressor, mimics many of the effects of nontraumatic stress in humans by resulting in increased food intake and adiposity, including enhancement of visceral fat growth. A second paper recently accepted at AJP, indicates that in dominant-subordinate pairings, only the losers (defeated hamsters) and not the winners (dominant hamsters) show these changes.
Bartness and Huhman hope that this model can be exploited in the future to uncover the brain mechanisms underlying this whole process. With such knowledge, it might be possible to generate pharmacological approaches to attack stress-induced obesity in humans and block or reverse it.
Bartness credits the success of this research to graduate student interactions fostered by the CBN.
"What really got this research going was the friendship between Matia Solomon in Dr. Huhman's lab and Michelle Foster in my lab. They are the energy behind getting this research off the ground and did all the work. It would have never happened if it wasn't for the CBN, that is for sure."
* "Social Defeat Increases Food Intake, Body Mass, and Adiposity in Syrian Hamsters," was one of the most-frequently read articles in the May issue of the American Journal of Physiology.
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