Brain Chemicals Hold Key To Stopping Binge Eating

Researchers are trying to understand how orexins influence appetites and whether they can be used to treat addiction and obesity, Andy Extance reports for Chemistry World.

Photo Insert: The 2017–2020 US National Health and Nutrition Examination Survey found that 41.2% of adults in that country were obese.

To study how some little-known brain chemicals affect our eating behavior, Robyn Brown’s team is trying to frustrate mice with chocolate. At the University of Melbourne in Australia, her team prepares mice by giving them access to sweets for two hours every three days.

“That gets rodents very excited,” Brown tells Chemistry World. Eventually, test day comes. “We put food in a tea strainer and dangle it in the home cage,” Brown explains.

“They can see and smell the food, but they can’t actually get to it.” After stressing the mice in this way, the Melbourne researchers open the tea strainer. Then, some mice eat nearly two-thirds of their usual daily food intake in just 15 minutes.

Using her team’s new model, Brown hopes to study the role that signaling molecules called orexins might play in stress-induced binge eating. The lessons Brown’s team learns from these mice could have outsized significance. The 2019 Health Survey for England found that 28% of the country’s adults were obese.

The 2017–2020 US National Health and Nutrition Examination Survey found that 41.2% of adults in that country were obese. Brown underlines that a century ago, less than 10% of people were obese.

“Genetics can’t change that quickly,” she says.

Scientists discovered ghrelin, leptin, and orexins in the 1990s amid growing concern about obesity. They were enabled by new molecular biological methods involving genetic modification, cloning, and protein purification. Right from the orexins’ discovery in 1998, it was clear they had multiple roles.

In January and February of that year, two teams first published details of their existence, coming from completely different angles. Brown says orexins differ greatly from molecules known for controlling hunger, the hormones ghrelin, and leptin.

While ghrelin and leptin circulate through our bodies, orexins are neuropeptides, acting only in our brains. Zeroing in on orexins could help develop medicines that could prevent binge eating, a disorder that could potentially develop into a multi-billion-dollar segment of the global pharmaceuticals market.

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