Researchers have identified that a small group of brain cells in the hypothalamus could be a promising target for medications for controlling binge eating episodes in individuals with obesity.

The researchers said that "orexin" neurons -- named for the chemical messenger they use to communicate with other brain cells -- have previously been shown to be important for addiction to several drugs including cocaine. "Several key symptoms of eating disorders, such as the sense of losing control, overlap with what we know about the driven nature of drug addiction," said co-author Gary Aston-Jones from Rutgers, The State University of New Jersey in the US.

"Since the orexin system has been implicated in addiction to drugs of abuse, we targeted it to understand the change in food motivation caused by repeated episodes of binge eating," Aston-Jones added. For the study, presented at the 26th Annual Meeting of the Society for the Study of Ingestive Behavior, the researchers examined female rats fed a control diet or a sugary, high-fat diet that causes weight gain and binge eating patterns.

Then the researchers set up a task where rats could work to earn sweet treats. The researchers found that as the work required increased, persistent motivation to earn the treat was seen only in the binge-eaters who had previously gained weight on a high-fat diet. According to the researchers, notably, this enhanced motivation was reversed by treatment with a compound that blocks orexin signals in the brain.

"This study was really a proof-of concept for using orexin blockers to reduce binge-like eating in rodents," said the lead author Morgan James from Rutgers, The State University of New Jersey. The researchers also found that the orexin blocker reduced the amount of food consumed during the binge eating episodes, where rats were given unrestricted access to a sweetened fat mixture over a 30 minute period.