Bethesda, MD (August 14, 2006) -- Some brains may be wired to encourage fidgeting and other restless behaviors that consume calories and help control weight, according to new research published by The American Physiological Society.
The study found that the brains of rats bred to be lean are more sensitive to a chemical produced in the brain, orexin A, which stimulates appetite and spontaneous physical activity such as fidgeting and other unconscious movements. Compared to rats bred to be obese, the lean rats had a far greater expression of orexin receptors in the hypothalamus.
"The greater expression of orexin receptors suggests the lean rats' brains were more sensitive to the orexin the brain produces," said Catherine M. Kotz, the study's senior researcher. "The results point to a biological basis for being a couch potato."
This line of research suggests that frequent minor unconscious movements such as fidgeting and other behaviors associated with restlessness burn calories and help control weight, Kotz said. Further, it suggests a strategy to reduce weight gain and could lead to the development of a drug to stimulate minor activity.
The study "Elevated hypothalamic orexin signaling, sensitivity to orexin A and spontaneous physical activity in obesity resistant rats," appears in the online edition of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology published by The American Physiological Society. The study was done by Jennifer A. Teske and Allen S. Levine of the University of Minnesota and the Minnesota Obesity Center, St. Paul; Michael Kuskowski, VA Medical Center, Minneapolis; James A. Levine, Mayo Clinic, Rochester, Minnesota; and Catherine M. Kotz, the VA Medical Center, University of Minnesota, and the Minnesota Obesity Center.
Study looks at obese versus lean rats