title: Histamine-2 receptor expression in gastric mucosa before and after Helicobacter pylori cure.
abstract: BACKGROUND
  Helicobacter pylori infection prevents the occurrence of the tolerance phenomenon of Histamine-2 (H2) receptor antagonists. Gastro-esophageal reflux disease develops in some cases with the restoration of acid secretion after H. pylori eradication therapy.
  
  
  OBJECTIVE
  To clarify the mechanisms of H2 receptor restoration after the eradication of H. pylori on parietal cells.
  
  
  METHODS
  We enrolled 80 consecutive asymptomatic male patients with H. pylori infection, having chronic gastritis with or without the presence of peptic ulcers. Biopsy specimens from the greater curvatures at the mid-corpus of the stomach were obtained endoscopically from all subjects before and 12 weeks after the eradication of H. pylori. Degrees of gastric atrophy were evaluated by serum pepsinogen levels. The amounts of mRNA expression of H2 receptor were evaluated in each subject's gastric mucosa by real time reverse transcriptase-polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  H2 receptor mRNA expression levels significantly correlated with serum pepsinogens I and II ratios. The expression level of H2 receptor mRNA was lower in subjects with hypergastrinemia. The median expression level of H2 receptor after H. pylori eradication was threefold greater than prior to treatment. In addition, its restoration became more pronounced in subjects with severe gastric atrophy. However, a comparatively low restoration of H2 receptor mRNA was found in subjects with hypergastrinemia.
  
  
  CONCLUSIONS
  H2 receptor mRNA levels decrease with the progression of gastric atrophy induced by H. pylori infection, and are restored after H. pylori eradication. Such expression levels of H2 receptor may explain a part of the tolerance phenomenon to H2 receptor antagonists.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, Jichi Medical School, Kawachi, Tochigi, Japan. osawa@jichi.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Osawa
authors.forename: H
authors.initials: H
authors.lastname: Kita
authors.forename: H
authors.initials: H
authors.lastname: Ohnishi
authors.forename: H
authors.initials: H
authors.lastname: Mutoh
authors.forename: Y
authors.initials: Y
authors.lastname: Ishino
authors.forename: K
authors.initials: K
authors.lastname: Satoh
authors.forename: K
authors.initials: K
authors.lastname: Sugano
mesh_terms: D000900:Anti-Bacterial Agents; D004359:Drug Therapy, Combination / Q000627:therapeutic use*; D005744:Gastric Acid / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism / Q000382:microbiology; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000378:metabolism; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D011970:Receptors, Histamine H2 / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000900:Anti-Bacterial Agents; D012333:RNA, Messenger; D011970:Receptors, Histamine H2