How a protein meal tells your brain you are full

July 5, 2012, Cell Press
Feeling full involves more than just the uncomfortable sensation that your waistband is getting tight. Investigators reporting online on July 5th in the Cell Press journal Cell have now mapped out the signals that travel between your gut and your brain to generate the feeling of satiety after eating a protein-rich meal. Understanding this back and forth loop between the brain and gut may pave the way for future approaches in the treatment and/or prevention of obesity. Credit: Duraffourd et al., Cell

Feeling full involves more than just the uncomfortable sensation that your waistband is getting tight. Investigators reporting online on July 5th in the Cell Press journal Cell have now mapped out the signals that travel between your gut and your brain to generate the feeling of satiety after eating a protein-rich meal. Understanding this back and forth loop between the brain and gut may pave the way for future approaches in the treatment and/or prevention of obesity.

Food intake can be modulated through mu- (MORs, which also bind morphine) on nerves found in the walls of the portal vein, the major blood vessel that drains blood from the gut. Specifically, stimulating the receptors enhances food intake, while blocking them suppresses intake. Investigators have now found that peptides, the products of digested dietary proteins, block MORs, curbing appetite. The peptides send signals to the brain that are then transmitted back to the gut to stimulate the intestine to release glucose, suppressing the desire to eat.

Mice that were genetically engineered to lack MORs did not carry out this release of glucose, nor did they show signs of 'feeling full', after eating high-protein foods. Giving them MOR stimulators or inhibitors did not affect their food intake, unlike normal mice.

This image shows the process of the appetite-suppressing effect of proteins. Credit: Inserm / F. Koulikoff

Because MORs are also present in the neurons lining the walls of the in humans, the mechanisms uncovered here may also take place in people.

"These findings explain the satiety effect of , which is a long-known but unexplained phenomenon," says senior author Dr. Gilles Mithieux of the Université de Lyon, in France. "They provide a novel understanding of the control of and of hunger sensations, which may offer novel approaches to treat obesity in the future," he adds.

Explore further: Gut hormone receptor in brain is key to gastric emptying rate; may help prevent obesity

More information: Duraffourd et al.: "Mu-Opioid Receptors and Dietary Protein Stimulate a Gut-Brain Neural Circuitry Limiting Food Intake." Cell, DOI:10.1016/j.cell.2012.05.039

Abstract
Intestinal gluconeogenesis is involved in the control of food intake. We show that mu-opioid receptors (MORs) present in nerves in the portal vein walls respond to peptides to regulate a gut-brain neural circuit that controls intestinal gluconeogenesis and satiety. In vitro, peptides and protein digests behave as MOR antagonists in competition experiments. In vivo, they stimulate MOR-dependent induction of intestinal gluconeogenesis via activation of brain areas receiving inputs from gastrointestinal ascending nerves. MOR-knockout mice do not carry out intestinal gluconeogenesis in response to peptides and are insensitive to the satiety effect induced by protein-enriched diets. Portal infusions of MOR modulators have no effect on food intake in mice deficient for intestinal gluconeogenesis. Thus, the regulation of portal MORs by peptides triggering signals to and from the brain to induce intestinal gluconeogenesis are links in the satiety phenomenon associated with alimentary protein assimilation.

Related Stories

Gut hormone receptor in brain is key to gastric emptying rate; may help prevent obesity

June 25, 2012
Researchers have discovered how a hormone in the gut slows the rate at which the stomach empties and thus suppresses hunger and food intake. Results of the animal study will be presented at The Endocrine Society's 94th Annual ...

Effects of exercise on meal-related gut hormone signals

July 12, 2011
Research to be presented at the upcoming annual meeting of the Society for the Study of Ingestive Behavior (SSIB), the foremost society for research into all aspects of eating and drinking behavior, finds that alterations ...

Gut bugs might influence child's odds for obesity

May 10, 2012
(HealthDay) -- Levels of certain gut bacteria and low protein intake may raise children's risk of being obese, new research suggests.

Recommended for you

Scientists solve the case of the missing subplate, with wide implications for brain science

June 21, 2018
The disappearance of an entire brain region should be cause for concern. Yet, for decades scientists have calmly maintained that one brain area, the subplate, simply vanishes during the course of human development. Recently, ...

LincRNAs identified in human fat tissue

June 21, 2018
A large team of researchers from the U.S. and China has succeeded in identifying a number of RNA fragments found in human fat tissue. In their paper published in the journal Science Translational Medicine the group describes ...

Key molecule of aging discovered

June 21, 2018
Every cell and every organism ages sooner or later. But why is this so? Scientists at the German Cancer Research Center in Heidelberg have now discovered for the first time a protein that represents a central switching point ...

Compound made inside human body stops viruses from replicating

June 20, 2018
The newest antiviral drugs could take advantage of a compound made not by humans, but inside them. A team of researchers has identified the mode of action of viperin, a naturally occurring enzyme in humans and other mammals ...

Research reveals zero proof probiotics can ease your anxiety

June 20, 2018
If you're expecting probiotics to reduce your anxiety, it might be time to put down that yogurt spoon—or supplement bottle—and call a professional instead.

Long-term estrogen therapy changes microbial activity in the gut, study finds

June 20, 2018
Long-term therapy with estrogen and bazedoxifene alters the microbial composition and activity in the gut, affecting how estrogen is metabolized, a new study in mice found.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.