The enteric nervous system that regulates our gut is often called the body’s “second brain.” Although it cannot solve problems like the brain, this extensive network uses the same chemicals and cells as the brain to help us digest and to alert the brain when something is amiss. However, how enteric neural circuits respond to changes in the gut is not fully understood. Now, University of Calgary researchers report they have designed a novel imaging and experimental preparation system, allowing them to record the activity of the enteric nervous system in mice.
The findings are published in the Journal of Physiology in a paper titled, “Intestinal distension orchestrates neuronal activity in the enteric nervous system of adult mice.”
“The enteric nervous system (ENS) regulates the motor, secretory, and defensive functions of the gastrointestinal tract,” wrote the researchers. “Enteric neurons integrate mechanical and chemical inputs from the gut lumen to generate complex motor outputs. How intact enteric neural circuits respond to changes in the gut lumen is not well understood. We recorded intracellular calcium in live-cell confocal recordings in neurons from intact segments of mouse intestine in order to investigate neuronal response to luminal mechanical and chemical stimuli.”
“This completely different way of conducting experiments allows us to better understand the complexity of the nerve interactions that are regulating and coordinating the responses by the gut’s nervous system,” explained Wallace MacNaughton, PhD, co-principal investigator. “It opens up new avenues for us to understand what’s really going on, and that’s going to help us understand gastrointestinal diseases and disorders a lot better.”
“This wave of excitation around the circumference of the gut, and the change in neuronal excitability, have never been seen before,” said Keith Sharkey, PhD, co-principal investigator. “When the gut is distended, the nerve circuits respond in ways that are totally different than when the gut is relaxed.”
The team’s study is the first that shows, in an intact gut preparation, the role of the gut’s physical distention in controlling how the entire neural network in the gut is coordinated.
“We wanted all researchers to have access to this approach,” said Sharkey. “Gaining a better understanding of the physiology of the gut is fundamental to being able to understand what happens when it doesn’t work properly, and to developing effective treatments.”
The researchers are now planning to investigate how probiotics, inflammation, and bacterial infection alter the control and coordination of the gut’s nervous system in mice.
“This is giving us a model that may help us test new approaches to treating gastrointestinal diseases in people at some point in the future,” MacNaughton said.
