Your body’s ‘second brain’ lives in your gut, and it could be the key to treating GI disorders

There’s a lot more to the term “gut feeling” than you may realize. While you may be making all your decisions with your head, it turns out the human enteric nervous system is now being called the body’s “second brain” by scientists. In a recent study out of Michigan State University, researchers say a better understanding of the enteric system could lead to breakthrough treatments for gut conditions like irritable bowel syndrome.

“Most people don’t even know that they have this in their guts,” says Brian Gulbransen, a professor with MSU’s College of Natural Science’s Department of Physiology, in a statement.

The enteric nervous system is surprisingly independent. Researchers say the gastrointestinal (GI) tract can continue its normal functions when it receives no input from the central nervous system (CNS). “It’s like this second brain in our gut,” Gulbransen says. “It’s an extensive network of neurons and glial cells that line our intestines.”

Neurons are the more familiar of the two cell types. They conduct the electrical impulses generated by the nervous system. Glial cells are not electrically active, which has made it more challenging for researchers to elucidate the cells’ functions. One leading theory was that glia provide passive support for neurons.

Gulbransen and his team found that glial cells have a  precise influence on the signals carried by neuronal circuits. The team’s findings may be instrumental in the development of new treatments for intestinal disorders that affect as many as 15% of the U.S. population.

“This is a ways down the line, but now we can start to ask if there’s a way to target a specific type or set of glia and change their function in some way,” Gulbransen says. “Drug companies are already interested in this.”

Gulbransen’s team reports that understanding glia function generates new ways to help treat irritable bowel syndrome. The condition can be very painful and disruptive, profoundly adversely affecting quality of life. There is no cure for IBS which affects 10% to 15% of Americans. “Right now, there’s no known cause. People develop what looks like an obstruction in the gut, only there’s no physical obstruction,” Gulbransen explains. “There’s just a section of their gut that stops working.”

Glia could be involved in other GI disorders, including gut motility disorders, such as constipation, and a rare disorder known as chronic intestinal pseudo-obstruction.

Gulbransen stresses that the findings need more work and are not ready for development into treatments for GI disorders. The new knowledge of the enteric nervous system does better equip scientists to probe deeper into their discoveries, and to understand them more fully. 

The study is published in the Proceedings of the National Academy of Sciences.

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