Advances in Neo-Innervation of the Gut

The gastrointestinal (GI) tract is a hollow organ composed of epithelial, muscular, and neural components, along with supporting cells, including interstitial cells of Cajal and endothelial cells, which cooperate to support digestion. The inner layer, or mucosa consists of epithelial cells that secrete digestive enzymes/acid, absorb nutrients, facilitate hormone secretion, and assess the luminal content of the gut. Constant sampling of luminal materials is coordinated by receptors expressed on the apical side of epithelial cells within the mucosa that can transmit signals to other systems such as the enteric nervous system and the gut immune system. The mucosa is surrounded by circular and longitudinal smooth muscle layers that promote the mechanical breakdown and propulsion of food within the GI tract, through coordinated contraction and relaxation events termed peristalsis. The neural component of the GI tract, the enteric nervous system, is an independent division of the peripheral nervous system responsible for regulating gut functions including motility, secretion, and absorption.