Beneath the epithelial cells that line the gastrointestinal tract is a network of fibroblasts. These are thought to regulate the behaviour of the epithelial cells above and are in close contact with nerve terminals in the tissue. Sonoko Furuya and co-workers now reveal that the subepithelial fibroblasts also function as mechanosensors (see ). They find that mechanical stress – stretching the cells or touching them with a glass rod – causes them to contract and release ATP. This activates P2Y receptors on neighbouring cells, generating intracellular calcium waves that are propagated through the fibroblast network. The authors demonstrate that, in cocultures, these waves also propagate to neighbouring NG108-15 neural cells, which express P2Y and P2X receptors. Similar receptors are present on sensory nerves in intestinal villi. Furuya and co-workers therefore propose that mechanosensory responses of subepithelial fibroblasts to stresses caused by nutrient uptake might in this way provide a mechanism for regulation of peristalsis in the gut.
