Subcutaneous Loperamide Prevents Gastric Lesions Induced by Necrotizing Agents in Rats

The effects of subcutaneous loperamide ongastric lesions induced by necrotizing agents wereinvestigated in the rat. Loperamide produced adose-dependent increase of gastric fluid volume andinhibition of gastric lesions caused by 0.6 N HCl orabsolute ethanol. Pretreatment with naloxone almostcompletely blocked both fluid pooling effect and mucosalprotective effect of loperamide. Omeprazole reduced the acidity of the gastric fluid in ratstreated with loperamide without significantly decreasingthe fluid volume. Various volumes of acid, given orallyimmediately before 0.6 N HCl, volume-dependently prevented gastric lesions. We conclude thatsubcutaneous loperamide protects the gastric mucosaagainst necrotizing agents through luminal dilution ofirritants, which is mediated by naloxonesensitive opiate receptors.