Monitoring Gut Epithelium Serotonin and Melatonin Overflow Provides Spatial Mapping of Inflammation

Electrochemical arrays were used to measure the overflow of serotonin (5‐HT) and melatonin (MEL) from the entire colon of healthy mice and mice with chemical‐induced inflammatory bowel disease (IBD), to understand the interplay between inflammation and colonic function. We show that 5‐HT overflow is increased, whilst MEL levels are reduced, in inflamed tissues. The levels of MEL are increased at the interface between healthy and inflamed regions within the colon and may limit the spread of inflammation. Understanding the interplay between inflammation and mucosal epithelial signalling can provide key insight into colonic function and aid the development of effective therapeutic strategies to treat gastrointestinal diseases.