Direct gut-brain connection mapped

Researchers have found that cells lining the stomach and intestines have special arms to connect to a neuronal circuit that provides real time information to the brain as to what is happening in the gut.

The findings could provide new insight into how people sense being full after eating and how food borne viruses could infect the nervous system.

"The study supports the idea that there could be a real biology of gut feelings," said Diego BohArquez, an assistant professor of medicine at Duke University in the US.

"As soon as food contacts the wall of the gut, the brain will know in real time what is going on in the gut," BohArquez noted.

The researchers earlier found a type of cell scattered throughout the lining of the mouse gut that is remarkably similar to a neuron.

Although the cells have a normal shape on the gut's surface, their underside bears a long arm.

Dubbed 'neuropods', these special arms are nurtured by support cells known as glia that work with neurons, which suggested at the time that they could be involved in a neuronal circuit.

In the new study, researchers traced the contacts of the neuropods in greater detail.

They found that about 60 percent of neuropods contacted sensory neurons, supporting the notion that they could be involved in gut sensation.

They also showed that neuropods and neurons not only contact one another, but they connect.

When the researchers introduced rabies virus in mice, only cells with neuropods became infected.

"That provides a pathway where rabies can go from the lumen of the gut to the nervous system," Rodger Liddle from Duke University explained.

"It implies you might be able to get rabies by eating rabies," Liddle added.

The study appeared in the Journal of Clinical Investigation.