Study shows how brain chemicals control eating, could help develop improved obesity drugs   

A study has found that brain chemicals such as dopamine and serotonin work together in controlling hunger and food intake. A finding which can possibly help in developing improved anti-obesity drugs.

Working with animal models, researchers, including those at the Baylor College of Medicine, US, found that two brain chemicals—the excitement-causing dopamine and calm-inducing GABA, or gamma-aminobutyric acid—arrest the production of serotonin when one initiates a meal.

Serotonin, known to act as a ‘mood stabiliser’ and produce calming effects, is created mainly in the dorsal Raphe nucleus, located in the midbrain—the topmost part of the brain stem that connects the brain to the spinal cord.

“Working with animal models, we found that when animals are hungry, serotonin-producing neurons in the (dorsal Raphe nucleus) are inhibited by GABA and dopamine. This reduces the levels of serotonin in the brain, which allows the initiation of a meal,” Yong Xu, a professor of pediatrics-nutrition and corresponding author of the study published in the journal Metabolism, said.

As the animals feed and reach satiety, more serotonin is produced, which then travels to the ‘arcuate of the hypothalamus’, or ARH, thereby conveying a message to ‘slow down on eating’, Xu explained. The ARH region monitors energy in the body and regulates metabolic responses.

“What’s unique about this is that GABA and dopamine act synergistically (together) -- when both are present, serotonin neurons appear to be more inhibited than when only one of the neurotransmitters is present,” the author said.

The work helps improve our understanding of how the brain manages body weight and feeding, specifically the roles of brain chemicals while feeding, the researchers said.

This knowledge can inform the development of improved obesity drugs, they added.