Effects of 4-(4-bromophenyl)-2-methyl-1,2,3,4-tetrahydroisoquinoline hydrochloride on acute gastric lesions, acid secretion in rats and on some hemodynamic parameters in cats.

The effectiveness of 4-(4-bromophenyl)-2-methyl- 1,2,3,4-tetrahydroisoquinoline hydrochloride (AN 12 ) on acute ulcer models and gastric acid secretion in rats was compared with the action of the histamine H 2 -receptor antagonist roxatidine (R), AN 12 or R given orally, produced significant, dose-dependent decreases in stress- and indomethacin-induced ulcers. The ED 50 value of AN 12 and R were 0.40 (0.27-0.60) and 13.27 (9.13-19.29) mg/kg, respectively, for stress ulcers and 0.68 (0. 17-2.61) and 25 mg/kg, respectively, for indomethacin ulcers, The length and number of ethanol-provoked gastric damages were significantly reduced by R (50 and 100 mg/kg p.o.) but not by AN 12 (0.5-2 mg/kg p.o. ). In pylorus-ligated rats, AN 12 (2 mg/kg p.o.) and R (50 and 100 mg/kg p.o.) significantly inhibited basal gastric acid secretion, increased pH and decreased acidity, The influence of AN 12 (2 mg/kg) on the volume of stomach juice was close to that of R (100 mg/kg ). AN 12 (0. 1-1.0 mg/kg i.v.) did not significantly affect the hemodynamics of anesthetized cats, It is suggested that the influence of some CNS amine neurotransmitters may lie included in part, in the effects of AN 12 .