Involvement of the Gut Chemosensory System in the Regulation of Colonic Anion Secretion

A Kuwahara

doi:10.1155/2015/403919

Abstract

The primary function of the gastrointestinal (GI) tract is the extraction of nutrients from the diet. Therefore, the GI tract must possess an efficient surveillance system that continuously monitors the luminal content for beneficial or harmful compounds. Recent studies have shown that specialized cells in the intestinal lining can sense changes in this content. These changes directly influence fundamental GI processes such as secretion, motility, and local blood flow via hormonal and/or neuronal pathways. Until recently, most studies examining the control of ion transport in the colon have focused on neural and hormonal regulation. However, study of the regulation of gut function by the gut chemosensory system has become increasingly important, as failure of this system causes dysfunctions in host homeostasis, as well as functional GI disorders. Furthermore, regulation of ion transport in the colon is critical for host defense and for electrolytes balance. This review discusses the role of the gut chemosensory system in epithelial transport, with a particular emphasis on the colon.

Highlights

The primary function of the gastrointestinal (GI) tract is obtaining energy sources from the diet as nutrients
As colonic mucosa is continuously exposed to noxious chemicals, including toxic compounds such as bacterial metabolites and the products of oxidative stress, in addition to nutrients, the chemosensory system in the gut is critical for distinguishing the nutrients from the other luminal contents
Gut luminal chemosensing involving FFA2, FFA3, T2R, Odorant Receptor (OR), and transient receptor potential A1 (TRPA1) may act as a line of defense against noxious agents, preventing the large intestine from being exposed to these agents

Summary

Kuwahara

Laboratory of Physiology, School of Food and Nutritional Sciences/Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, 422-8526, Japan. Recent studies have shown that specialized cells in the intestinal lining can sense changes in this content. These changes directly influence fundamental GI processes such as secretion, motility, and local blood flow via hormonal and/or neuronal pathways. Most studies examining the control of ion transport in the colon have focused on neural and hormonal regulation. Study of the regulation of gut function by the gut chemosensory system has become increasingly important, as failure of this system causes dysfunctions in host homeostasis, as well as functional GI disorders. Regulation of ion transport in the colon is critical for host defense and for electrolytes balance. This review discusses the role of the gut chemosensory system in epithelial transport, with a particular emphasis on the colon

Introduction

SCFA Receptors

Bitter Taste Receptors

TRP Channels

Findings

Conclusion