��Թ� State Biologist Secures NIH Support to Expand Study into Muscle Thermogenesis

Scientists have long since established that the effects of stress on our bodies are largely negative. But understanding stress as a trigger for using calories and burning fat also could lead us to better mechanisms for healthier behaviors.

The National Institutes of Health (NIH) recently funded a ��Թ� researcher to continue her efforts toward that goal.

Based on a recently-published study, Colleen Novak, associate professor of biological sciences in the College of Arts and Sciences, will use a three-year, $447,000 grant to analyze two new elements believed to drive muscle thermogenesis.

Novak’s previous study, recently accepted by the Journal of Experimental Biology, showed that rats exposed to predator odors burned more calories and ran for longer periods.

“This is a completely previously-undiscovered physiological response to predator threat,” she said. “To my knowledge, nobody but us actually measures skeletal muscle heat in animals.”

Rats exposed to the odor displayed increased muscle temperature within minutes, and all lost weight. They also were able to run longer by at least five minutes.

The study further showed that exposure to certain conditions, coupled with predator odor, yielded a learned response, wherein the conditions themselves became stressful, with or without predator odor.

Novak said all of this was driven by the sympathetic nervous system.  She’ll now leverage that insight into a study of a specific part of the brain and specific changes in the muscles, which both may drive thermogenesis. 

“We are the only ones I know trying to figure out the neural control of muscle thermogenesis," Novak said. "Even the folks who investigate the muscle biochemical and cellular mechanisms look at things like weight gain and loss on different diets, or reaction to cold, rather than measuring the actual muscle temperature. So this is completely new.”

Novak will first study a specific cell group in the brain region called the ventromedial hypothalamus — known to play key roles in the control of metabolism and the behavioral response to predator threat.  

“If you block these cells, then animals don’t act the same around predators, like trying to escape,” she said. “We think this set of cells is important to the capacity to show physiological responses to predator threat as well.”

Novak also will analyze which specific changes in the muscle generate heat. “There are a few possibilities, but we are focusing on a calcium channel,” she said. “We hypothesize that this pump that shuttles calcium from one part of the muscle cell to another uses more energy and/or pumps less calcium. Essentially, there is an ‘uncoupling’ of this channel. The wasted energy is dissipated as heat. We are also measuring levels of proteins in the muscle which have the job of uncoupling this calcium channel.”

Media Contact
 Dan Pompili: 330-672-0731, dpompili@kent.edu