Sternini Catia, Anselmi Laura, Rozengurt Enrique
Division of Digestive Diseases and CURE: Digestive Diseases Research Center, and Departments of Medicine, USA.
Curr Opin Endocrinol Diabetes Obes. 2008 Feb;15(1):73-8. doi: 10.1097/MED.0b013e3282f43a73.
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.
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.
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.
本综述讨论胃肠道肠内分泌细胞作为化学感受器的作用，这些细胞感知管腔内容物，并通过释放作用于各种局部或远处靶点的信号物质来诱导胃肠道功能和食物摄入的变化。
最近的证据支持这样一种概念，即肠道中的化学感应涉及G蛋白偶联受体和效应器，这些受体和效应器已知可介导口腔中的味觉信号。其中包括甜味和苦味受体及其相关的G蛋白，它们在胃肠道黏膜中表达，包括特定群体的肠内分泌细胞。此外，味觉受体激动剂在体外和动物体内均可引起肠内分泌细胞的分泌反应，并诱导神经元激活。
胃肠道黏膜中表达的味觉信号分子可能参与管腔中营养物质和有害物质的功能检测，并使肠道做好吸收它们或启动保护反应的准备。它们也可能通过激活肠-脑神经通路参与食物摄入的控制。这些发现为揭示由胃肠道管腔内容物引发的调节回路提供了一个新的维度。
