Different effects of two types of H _2-receptor antagonists, famotidine and roxatidine, on the mucus barrier of rat gastric mucosa

摘要

Compared with the aggressive factors, little attention has been paid to the mucosal defensive factors in ulcer therapy, and the role of the H _2-receptor antagonists in gastric mucosal protection has not been well characterized. In the present study, the effects of different types of H _2-receptor antagonists (famotidine and roxatidine) on rat gastric mucus cells were investigated using both biochemical and histological methods. Each drug (famotidine, 3 mg/kg; roxatidine, 100 mg/kg) was orally administered to rats by gavage once daily for 7 days. The biosynthesis and tissue content of mucin were compared in the gastric mucosa treated with each drug. Using anti-mucin monoclonal antibodies, the mucin content and immunohistochemical localization were also compared. Both the biosynthesis and the accumulation of gastric mucin were significantly decreased in the famotidinetreated rats, but not in the roxatidine. Both the content and the immunoreactivity of surface mucus cell-derived mucin were reduced by famotidine, while they were maintained in roxatidine-treated rat stomachs. There was no difference between the groups in the content and immunoreactivity of mucous neck cell-derived mucin. H _2-receptor antagonists should be classified in relation to gastric surface mucus cell function, raising the possibility of more effective ulcer therapy.