Ondansetron a 5-HT3 receptors antagonist increases gastric antral and fundic area after distension with 600 MI water in dyspeptic patients

Introduction: Previous studies have shown an involvement of 5-HT1 receptors in gastric relaxation and distension in bumam. There are no data on the effect of 5-HT3 receptors on gastric adaptation a~ter distension, Aim: Aim of the study has been to evaluate the effect of Ondansetron an inhibitor of 5-HT3 receptors, used orally or IV Dr the prevention of uausea and vomiting, on gastric size after distension with a liquid meal Materials and methods: In eighteen dyspeptm patients with normal upper g,i. endoscopy and ultrasonography (US) transverse gastric fundic and longitudinal amral area were determined by real time US after 600 ml water The water was ingested by each patient in a three min period and the gastric area was determined immediately by US at frte end of ingestion. Five mm before the water ingestion placebo or Ondansetmn ( 8 rag) were given IV in a double blind fashion. Placebo and Ondanselron were evaluated with an interval of 48 hours. Results: The results show after Ondansen'on in comparison with placebo a statistically significant increase in amral and fundic area (Antrum: Placebo 7,9 +-0,6 cm2, Ondansetron 12.8+-2,5, cm2, P<0.001; Fundus: Placebo 13,9+-2.3 cm2, ondansetron 26.8+-2.4 ,cm2,mean+-SD, POndansetron increases gastric amral and fimdic size after water ingestion suggesting a role [or 5-HT3 receptors in human gastric adaptation to liquid distension