The study conducted by Vaishali Bakshi and Ned Kalin, professors in the Department of Psychiatry at the University of Wisconsin-Madison School of Medicine and Public Health said that the system has attracted interest for its role in regulating food intake as it is mediated by a hormone receptor protein known as the corticotropin-releasing factor type 2 (CRF2) receptor.
"With the increasing focus on obesity, people are interested in finding targets that can be used to develop drugs that will reduce appetite and food intake without a lot of side effects," Bakshi said.
Previous studies had shown that with the activation of this receptor the amount of food voluntarily eaten by hungry rats decreases, an effect, which is called as, induced anorexia.
However, with the new study, it has been reported that CRF2 receptors in a single brain region, the lateral septum, mediate both feeding and their behaviors are associated with stress. This suggests that this protein might not be an ideal therapeutic target.
Although, by selectively stimulating the CRF2 receptors in the lateral septum, the team found that the rats, which were being treated on an average ate less overall because they spent less time at it.
"The reason that the rats were eating less after having CRF2 receptors stimulated in the lateral septum was because instead of eating they were spending most of their time exhibiting stress-like behaviors, such as excessive grooming," Bakshi said.
In addition, the suppressed eating might be secondary to the apparent stress-inducing effects of the receptor.
"We found anxiety-like responses at smaller doses than those required to get the reduction in feeding. In terms of the chicken and the egg, it suggests that maybe the stress comes first and that the reduction in feeding comes second," she said.
The study is to appear in the Journal of Neuroscience.