A new class of antiulcer drugs. I. Antiulcer effect of AN5, a 4-phenyl-tetrahydroisoquinoline derivative, on different experimental models of ulcer in rats.

The action of AN5 on experimental models of gastric ulcers induced by water-immersion stress, indomethacin and reserpine, or by pylorus ligation in rats has been studied. AN5 supresses the formation of ulcers in all experimental models. The strongest antiulcer effect is shown in relation to water-immersion stress-induced ulcers. From the broad pharmacological studies of AN5 on this model it can be seen that even a dose of 0.100 mg/kg has a high antiulcer activity. The increase of the dose leads to a regular increase of the antiulcer activity, the highest suppression of the ulcer index being reached at a dose of 1 mg/kg (86.15%). The comparative studies with ranitidine and cimetidine on the same experimental models of gastric ulcers show that AN5 possesses an antiulcer activity many times higher than that of the above-mentioned drugs.