The role of gastrointestinal vagal afferent fibres in obesity

Abstract

Gastrointestinal (GI) vagal afferents are a key mediatory of food intake. Through a balance of responses to chemical and mechanical stimuli food intake can be tightly controlled via the ascending satiety signals initiated in the GI tract. However, vagal responses to both mechanical and chemical stimuli are modified in diet-induced obesity (DIO). Much of the research to date whilst in relatively isolated/controlled circumstances indicates a shift between a balance of orexigenic and anorexigenic vagal signals to blunted anorexigenic and potentiated orexigenic capacity. Although the mechanism responsible for the DIO shift in GI vagal afferent signalling is unknown, one possible contributing factor is the gut microbiota. Nevertheless, whatever the mechanism, the observed changes in gastrointestinal vagal afferent signalling may underlie the pathophysiological changes in food consumption that are pivotal for the development and maintenance of obesity. Gastrointestinal vagal afferents play an important role in food intake regulation. In individuals on a healthy balanced diet the anorexigenic and orexigenic signals from the gastrointestinal are finely balanced to maintain a steady weight. However, under high fat diet conditions this balance is disrupted with orexigenic signals out weighing anorexigenic signals, leading to increased food intake and body mass.