Cells in the intestine can directly communicate with nerves, suggesting a way in which food and gut bacteria might affect the brain.
Intestinal cells called enteroendocrine cells regulate feeding behaviour, affecting the brain indirectly by secreting hormones. But these cells also have a protrusion called a neuropod. To find out whether this makes direct, physical contact with nerves in the intestine, Diego Bohórquez and his colleagues at Duke University in Durham, North Carolina, delivered a rabies virus (which typically infects neurons) to the colon of a mouse. They found that the virus first infected the intestinal cells and then passed into the animal's nervous system.
The neuropod might carry chemical signals from gut bacteria to the brain, and could allow viruses to spread from the intestine to the nervous system, the researchers suggest.
J. Clin. Invest. http://doi.org/x2x (2015)