Résumé
Famotidine ( Fam ) antagonized the effects of histamine on guinea pig atria and rat uteri MI vitro non-competitively,however the antagonisms of Ranitidine(Ran) and Cimetidine (Cim ) on hoistamine were competitive, their pA2 were 6. 24, 5. 16 and 4. 08 for guinea pig atria , 8. 26, 7. 22 and 6. 17 for rat uteri respectively. They reduced gastric secretion of acid and pepsin of pylorus ligated rats in dose-related manner, inhibited gastric secretion stimulated byhistamine, prevented the acute gastric lesion from stress, indomethacin and histamine, and enhanced the healing process of chronic gastirc ulcerinduced by acetic acid in rats. Moreover, Fam was much more potent than Ran (6~8 times) and Cim(30 - 40 times). Besides,Cim increased hypnotic effect of phenobartal, but Ran and Fam had no or Ittile such effects.