Chemosensitivity of the human gastrointestinal tract in health and in disease

Abstract

Although visceral sensitivity in man comprises chemosensitivity, thermosensitivity and mechanosensitivity, only the latter has been intensively studied. Studies in health have aimed at characterising the type of mechanoreceptors involved in visceral mechanosensitivity,. Several authors have studied the prevalence and relevance to the symptom pattern of hypersensitivity to visceral balloon distention in patients with functional gastrointestinal disorders. Chemosensitivity of the gastrointestinal tract in man has received much less attention. In this issue of Neurogastroenterology and Motility, intraluminal application of capsaicin is described as a tool to study chemosensitivity of the proximal gastrointestinal tract. The authors report how activation of chemosensitive pathways induces symptoms that differ from those induced by activation of mechanosensitive pathways, and propose to use capsaicin as a tool to study the prevalence and role of hypersensitivity to visceral chemosensitivity in patients with functional gastrointestinal disorders. Our current knowledge of visceral chemosensitivity of the human gastrointestinal tract in health and in disease is reviewed, with a specific focus on the interaction between mechano- and chemosensitive pathways.