Role of duodenal mucosal nerve endings in the acid‐induced duodenogastric sensorimotor reflex: Effect of benzocaine in healthy humans. Issue 5 (9th April 2013)

• Record Type: Journal Article
• Authors: Vanuytsel, T.; Karamanolis, G.; Vos, R.; Van, L.; Farré, R.; Tack, J.
• Is Part Of: Neurogastroenterology & motility. Volume 25:Issue 5(2013:May)
• Page Start: e353
• Page End: e361
• Publication Date: 2013-04-09
• Subjects: Gastrointestinal system -- Motility -- Periodicals; Gastrointestinal system -- Innervation -- Periodicals; 616.33
• DOI: 10.1111/nmo.12126
• Languages: English
• ISSNs: 1350-1925

Abstract

<abstract abstract-type="main" id="nmo12126-abs-0001"> <title>Abstract</title> <sec id="nmo12126-sec-0001" sec-type="section"> <title>Background</title> <p>Duodenal acid exposure induces a duodenogastric reflex resulting in gastric relaxation, inhibition of antral motility, and sensitization of the proximal stomach to distension. Duodenal hypersensitivity to acid has been identified as a potential pathogenic mechanism in functional dyspepsia. The nature and localization of the duodenal acid‐sensitive receptors are still elusive. We hypothesize that acid directly activates superficial afferent nerve endings in the duodenal mucosa, triggering the duodenogastric reflex.</p> </sec> <sec id="nmo12126-sec-0002" sec-type="section"> <title>Methods</title> <p>In a double‐blind, randomized, crossover study in 13 healthy volunteers, benzocaine, a local anesthetic, <italic>vs</italic> saline was perfused in the duodenum 15 min before duodenal acid perfusion. Gastric responses were monitored by a barostat. Stepwise isobaric gastric distensions were performed before and during acid perfusion. Symptoms were evaluated by visual analogue scales for six dyspeptic symptoms and an overall perception score.</p> </sec> <sec id="nmo12126-sec-0003" sec-type="section"> <title>Key Results</title> <p>Benzocaine perfusion caused a relaxation of the stomach prior to duodenal acidification, indicating the existence of an excitatory duodenogastric tone. Pretreatment of the duodenum with benzocaine reduced the acid‐induced gastric relaxation by 50% and abolished the inhibition of phasic motility of the proximal stomach. Finally, sensitization to distension was more pronounced in the benzocaine condition because of higher proximal gastric volumes.</p> </sec> <sec id="nmo12126-sec-0004" sec-type="section"> <title>Conclusions & Inferences</title> <p>These findings support a model in which different neuronal subpopulations are responsible for the motor and sensory limb of the acid‐sensitive duodenogastric reflex, making benzocaine an unsuitable drug to treat duodenal hypersensitivity to acid. These data provide more insight in the contribution of duodenal neuronal input to gastric physiology in the fasting state.</p> </sec> </abstract>