Comparison of the protective effect of (R)-alpha-methylhistamine and its prodrugs on gastric mucosal damage induced by ethanol in the rat.

1. The gastroprotective activity of two azomethine prodrugs of (R)-alpha-methylhistamine was examined in lesions induced by absolute ethanol (1 ml/rat intragastrically for 1 h). 2. Pretreatment with (R)-alpha-methylhistamine as well as with the prodrugs (30 and 100 mg/kg intragastrically [IG]) significantly reduced macroscopically visible lesions caused by ethanol, with protection being almost complete at 100 mg/kg. 3. Histologically, in rats pretreated with the three compounds at a dose of 100 mg/kg, the evidence of damage was rare, with the appearance of gastric mucosa being similar in the different groups. 4. Present results are suggestive of a local component in the protective activity of (R)-alpha-methylhistamine.