Results from a study published in Neuropsychopharmacology suggest that administering a peptide and hormone to a certain area in the brain may cut the desire for food.
In particular, researchers found that administering pituitary adenylate cyclase-activating peptide (PACAP), which is produced by neurons, to the central amygdala decreased food intake and subsequently led to weight loss.
The peptide and hormone PACAP is already known for its effects on food intake and body weight in the hypothalamus, the researchers noted, but this study is the first to show its effects on the amygdala, which is involved in fear but also in the emotional component of eating.
Data from the study, which was conducted in rats, also indicated the mechanisms through which PACAP decreases food intake when administered to the amygdala.
"We found that amygdalar PACAP reduces the amount of food eaten within meals, but not how many meals are consumed. In addition, we found that PACAP reduced the rate of intake of food. This means that, following administration of PACAP, models were eating more slowly," researcher Valentina Sabino, PhD, assistant professor of pharmacology and psychiatry, and co-director of the Laboratory of Addictive Disorder at Boston University School of Medicine, said in a press release.
The effects of PACAP also appeared to be dependent on the growth hormone brain-derived neurotrophic factor (BDNF).
"The effects of PACAP on food intake and body weight were absent when it was given together with another drug that blocks BDNF signaling, suggesting that PACAP acts through BDNF," Dr. Sabino said.
Further, because data demonstrated that PACAP not only affected how much food the rats ate but also the speed with which they ate, the studying findings may have implications for other conditions.
"The PACAP system may hypothetically be the target of medications to treat not only obesity but also binge-eating, a disease characterized by excessive, uncontrollable consumption of food within brief periods of time," co-author Pietro Cottone, PhD, associate professor of pharmacology and psychiatry and co-director of the Laboratory of Addictive Disorder at Boston University School of Medicine, said in the release.
Growing evidence suggests that the pituitary adenylate cyclase-activating peptide (PACAP)/PAC1 receptor system represents one of the main regulators of the behavioral, endocrine, and autonomic responses to stress. Although induction of anorexia is a well-documented effect of PACAP, the central sites underlying this phenomenon are poorly understood. The present studies addressed this question by examining the neuroanatomical, behavioral, and pharmacological mechanisms mediating the anorexia produced by PACAP in the central nucleus of the amygdala (CeA), a limbic structure implicated in the emotional components of ingestive behavior.