STRUCTURAL CHARACTERISTICS OF HISTAMINE H-2-RECEPTOR ANTAGONISTS THATSCAVENGE HYPOCHLOROUS ACID

Gastric and duodenal ulcers are characterized by hypersecretion of gas tric acid and pepsin, inflammation of the mucosa and an influx of neut rophils. These cells can produce reactive oxygen species after stimula tion. Particularly hydroxyl radicals and hypochlorous acid (HOCl) can be cytotoxic and damage the gastroduodenal mucosa. It has been shown t hat histamine H, receptor antagonists such as cimetidine, ranitidine a nd famotidine are good hydroxyl radical scavengers. This study was und ertaken to investigate whether these agents were able to scavenge the cytotoxic HOCl, and if so, which part of the molecule could be respons ible for this action. It appears that the sulfur atom in the compound is of importance for scavenging HOCl. This finding should be taken int o consideration in the development of new anti ulcer drugs, as HOCl is a detrimental factor in the pathophysiology of gastroduodenal ulcers.