Enteroendocrine cells: a site of 'taste' in gastrointestinal chemosensing.
OBJECTIVE
This review discusses the role of enteroendocrine cells of the gastrointestinal tract as chemoreceptors that sense lumen contents and induce changes in gastrointestinal function and food intake through the release of signaling substances acting on a variety of targets locally or at a distance.


RESULTS
Recent evidence supports the concept that chemosensing in the gut involves G protein-coupled receptors and effectors that are known to mediate gustatory signals in the oral cavity. These include sweet-taste and bitter-taste receptors, and their associated G proteins, which are expressed in the gastrointestinal mucosa, including selected populations of enteroendocrine cells. In addition, taste receptor agonists elicit a secretory response in enteroendocrine cells in vitro and in animals in vivo, and induce neuronal activation.


CONCLUSIONS
Taste-signaling molecules expressed in the gastrointestinal mucosa might participate in the functional detection of nutrients and harmful substances in the lumen and prepare the gut to absorb them or initiate a protective response. They might also participate in the control of food intake through the activation of gut-brain neural pathways. These findings provide a new dimension to unraveling the regulatory circuits initiated by luminal contents of the gastrointestinal tract.
Sternini
Catia
C
Division of Digestive Diseases and CURE: Digestive Diseases Research Center, and Departments of Medicine, USA. csternin@ucla.edu
Anselmi
Laura
L
Rozengurt
Enrique
E
D000818:Animals; D002628:Chemoreceptor Cells / Q000378:metabolism / Q000502:physiology*; D019858:Enteroendocrine Cells / Q000378:metabolism / Q000502:physiology*; D005768:Gastrointestinal Hormones / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D013268:Stimulation, Chemical; D013649:Taste / Q000502:physiology*; D015293:Transducin / Q000378:metabolism
D005768:Gastrointestinal Hormones; D043562:Receptors, G-Protein-Coupled; C075192:gustducin; D015293:Transducin