Pathobiology of visceral pain: Molecular mechanisms and therapeutic implications - IV. Visceral afferent contributions to the pathobiology of visceral pain

Functional bowel and other visceral disorders exhibit multiple characterist ics that suggest the presence of visceral hyperalgesia. The discomfort, pai n, and altered sensations (e.g., to intraluminal contents) that define the hyperalgesia typically arise in the absence of tissue insult or inflammatio n. Visceral hyperalgesia thus differs from somatic hyperalgesia, which is c ommonly associated with tissue injury and inflammation. Hyperalgesia could develop and be maintained by either peripheral or central mechanisms; the a ltered sensations associated with functional visceral disorders are contrib uted to by both peripheral and central mechanisms. The relative contributio ns of peripheral and central mechanisms are not well understood, and the fo cus in this Themes article is on potential peripheral contributions: sensit ization of visceral receptors, nerve injury, and ion channels.