Changes in the environment can increase body temperature by impacting neural signaling to physiological systems including muscle and brown adipose tissue. We hypothesize that the “fight or flight” response can translate to weight loss due to muscle thermogenesis. The stimulus for the sympathetic nervous system response was the odor of ferrets, a natural predator of rats. This predator odor (PO; towel with ferret odor) induces a rapid and robust increase in skeletal muscle thermogenesis in rats. To test our hypothesis, each rat (N=10) was surgically implanted with temperature transponders (IPTT-300; Bio Medic Data Systems) adjacent to brown adipose tissue and skeletal muscle (gastrocnemius, bilaterally). To determine if this impacted energy balance, all rats were maintained on a 25% caloric restriction diet for 2 weeks, and half of the rats were exposed to a new PO towel daily; the other half received a control stimulus. On the 1st, 8th, and 14th day, muscle temperatures were monitored for two hours after exposure to PO or control. After one week, rats with daily PO exposure lost, on average, 13.4 more grams of body weight than the control group. All PO-exposed rats showed habituation in their PO-induced thermogenic response after 2 weeks, but not 1 week, of continuous exposure. Body composition measurements (EchoMRI-700) showed that, unexpectedly, most of the weight lost by PO rats was lean mass as opposed to fat mass. Exploiting the neural pathway underlying PO-mediated muscle thermogenesis could lead to novel weight loss strategies.
Dr. Colleen M. Novak
Exposure to the odor of a predator increases calories expended and skeletal muscle thermogenesis. Here, we tested the hypothesis that the “fight or flight” response could be harnessed to augment weight loss. Rats were subjected to 25% calorie restriction while chronically exposed to either a control stimulus or the odor of a predator (ferret). Rats exposed to the predator odor during food restriction lost significantly more weight than the control rats with equal calorie restriction. The predator odor elicited a significant muscle thermogenic response, and the rats showed habituation after 2 weeks, but not 1 week, of exposure. Exploiting this hypothetical pathway to induce thermogenesis could be used as a novel weight loss strategy.
The poster for the presentation.