title: Inhibition of gastric perception of mild distention by omeprazole in volunteers.
abstract: OBJECTIVE
  To evaluate the effects of omeprazole on gastric mechanosensitivity in humans.
  
  
  METHODS
  A double lumen polyvinyl tube with a plastic bag was introduced into the stomach of healthy volunteers under fluorography and connected to a barostat device. Subjects were then positioned so they were sitting comfortably, and the minimal distending pressure (MDP) was determined after a 30-min adaptation period. Isobaric distensions were performed in stepwise increments of 2 mmHg (2 min each) starting from the MDP. Subjects were instructed to score feelings at the end of every step using a graphic rating scale: 0, no perception; 1, weak/vague; 2, weak but significant; 3, moderate/vague; 4, moderate but significant; 5, severe discomfort; and 6, unbearable pain. After this first test, subjects received omeprazole (20 mg, after dinner) once daily for 1 wk. A second test was performed on the last day of treatment.
  
  
  RESULTS
  No adverse effects were observed. Mean MDP before and after treatment was 6.3 ± 0.3 mmHg and 6.2 ± 0.5 mmHg, respectively. One subject before and 2 after treatment did not reach a score of 6 at the maximum bag volume of 750 mL. After omeprazole, there was a significant increase in the distension pressure required to reach scores of 1 (P = 0.019) and 2 (P = 0.017) as compared to baseline. There were no changes in pressure required to reach the other scores after treatment. Two subjects before and one after omeprazole rated their abdominal feeling < 1 at MDP, and mean (± SE) abdominal discomfort scores at MDP were 0.13 ± 0.09 and 0.04 ± 0.04, respectively. Mean scores induced by each MDP + 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 (mmHg) were 1.1 ± 0.3, 2.0 ± 0.4, 2.9 ± 0.5, 3.3 ± 0.4, 4.6 ± 0.3, 5.2 ± 0.3, 5.5 ± 0.2, 5.5 ± 0.3, 5.7 ± 0.3, and 5.4, respectively. After omeprazole, abdominal feeling scores for the same incremental pressures over MDP were 0.3 ± 0.1, 0.8 ± 0.1, 2.0 ± 0.4, 2.8 ± 0.4, 3.8 ± 0.4, 4.6 ± 0.4, 4.9 ± 0.3, 5.4 ± 0.4, 5.2 ± 0.6, and 5.0 ± 1.0, respectively. A significant decrease in feeling score was observed at intrabag pressures of MDP + 2 mmHg (P = 0.028) and + 4 mmHg (P = 0.013), respectively, after omeprazole. No significant score changes were observed at pressures ≥ MDP + 6 mmHg.
  
  
  CONCLUSIONS
  Although the precise mechanisms are undetermined, the present study demonstrated that omeprazole decreases mechanosensitivity to mild gastric distension.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, School of Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, Japan. iida@aichi-med-u.ac.jp
authors.forename: Akihito
authors.initials: A
authors.lastname: Iida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kaneko
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Konagaya
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Funaki
authors.forename: Kentaro
authors.initials: K
authors.lastname: Tokudome
authors.forename: Shinya
authors.initials: S
authors.lastname: Izawa
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tamura
authors.forename: Mari
authors.initials: M
authors.lastname: Mizuno
authors.forename: Naotaka
authors.initials: N
authors.lastname: Ogasawara
authors.forename: Makoto
authors.initials: M
authors.lastname: Sasaki
authors.forename: Kunio
authors.initials: K
authors.lastname: Kasugai
mesh_terms: D000328:Adult; D000897:Anti-Ulcer Agents / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D009853:Omeprazole / Q000494:pharmacology*; D010465:Perception / Q000187:drug effects*; D011312:Pressure; D013270:Stomach / Q000187:drug effects*; D055815:Young Adult
chemical_list: D000897:Anti-Ulcer Agents; D009853:Omeprazole
keywords: Acid exposure; Barostat test; Functional dyspepsia; Mechanosensitivity; Ome-prazole