Researchers at Michigan State University have uncovered a potential explanation for the prevalence of visceral pain in individuals who have experienced gut inflammation, such as those with irritable bowel syndrome (IBS). Using mouse models, MSU physiologists demonstrated that glial cells in the nervous system can sensitize nearby neurons, lowering their activation threshold and making them more prone to sending pain signals post-inflammation.
Brian Gulbransen, senior author on the paper published in Science Signaling, likened the glial effect to dropping the threshold for neuron activation, turning non-painful stimuli into painful sensations. This discovery holds promise for developing therapies that counteract glial sensitization to alleviate or eliminate visceral pain, a common issue in gastrointestinal disorders.
While no medications currently target glial cells directly, pharmaceutical companies are exploring this avenue. The team's findings contribute valuable insights into potential therapeutic strategies. However, it's important to note that the study focused on nociception—the signals the nervous system sends in response to physical stimulus—rather than directly measuring pain. Gulbransen emphasized the distinction between nociception and pain, underscoring the need for cautious extrapolation of results from animals to humans.
The study delves into the enteric nervous system, often referred to as the "second brain," which runs through the gastrointestinal tract. Glial cells, once considered silent and passive, were found to play an active role chemically, responding to various compounds in the body and releasing biochemicals in response. Inflammation triggered glial cells to release compounds that altered gut chemistry, sensitizing nerve fibers.
First author Wilmarie Morales-Soto spearheaded the investigation, utilizing advanced genetic and chemical techniques to observe glial cell behavior before and after gut inflammation. The team's discoveries pave the way for future exploration into visceral pain, particularly its links to factors such as gender differences and early-life adversity. Understanding the role of glia in these situations could lead to innovative approaches for treating gut pain, offering hope for individuals grappling with gastrointestinal issues.