The Role of Vagal Afferent Nerves in Feeding Regulation

Abstract

Feeding is an essential type of behavior for maintenance of life activities. Regulation of feeding is necessary for the control of body energy balance, and its dysfunction leads to obesity and malnutrition. Recent studies have identified multiple neural circuits that contribute to homeostatic feeding and hedonic feeding, these circuits acting in a coordinated manner to regulate feeding overall. The hypothalamus and brainstem play important roles in homeostatic regulation. Hedonic feeding, which is regulated by the reward system including dopaminergic neurons in the ventral tegmental area, manifests as hyperphagia for palatable diets rather than for control of body energy balance. In this review article, we first review the mechanism of food intake regulation including homeostatic and hedonic feeding. Food intake alters peripheral energy status, hormones and metabolites in the body. These associated peripheral factors send information to the brain via two distinct routes: the blood‐brain barrier (humoral pathway) and the vagal afferents (neural pathway). Finally, we review the functions of the vagal afferent nerves that transmit meal-associated peripheral factors to the brain.