[Gut nutrient sensing by the abdominal vagus].

Gustatory and anticipatory cephalic stimuli that are detected during a meal yield nutritional information and aid in the efficient digestion of food. It is possible that animals can detect the amount of dietary food and its quality via cephalic relay to initiate proper digestion in the alimentary tract. The abdominal vagus conveys primary afferent nutritional information from the digestive system to the brain and modulates gastrointestinal motor and secretory activity that ensures the food digestion through local and central reflexes. Almost all the 5-HT in the body exists in the enterochromaffin (EC) cells in the alimentary tract, but the physiological significance of the mucosal 5-HT is not well elucidated. In the present paper, we reviewed recent advances in studies on gut nutrient perception and proposed the hypothesis that 5-HT derived from EC cells acts as a general transmitter of gut nutrient sensing by the abdominal vagus.