Effect of 2,4-diamino-6-(2,5-dichlorophenyl)-s-triazine maleate (MN-1695) on gastric mucosal blood flow in dogs.

The effect of 2,4-diamino-6-(2,5-dichlorophenyl)-s-triazine maleate (MN-1695) on gastric mucosal blood flow ( GMBF ) and on the changes of GMBF induced by catecholamines, tetragastrin, histamine and indomethacin were investigated in anesthetized dogs. MN-1695 at doses up to 1 mumol/kg i.v. showed only a slight but prolonged increase of GMBF . MN-1695 tended to inhibit the decreases of GMBF induced by norepinephrine and the increase of GMBF induced by tetragastrin. The later phase of decreased GMBF induced by histamine was suppressed by MN-1695. However, MN-1695 had almost no effect on the increase of GMBF induced by epinephrine. MN-1695 produced a marked increase of antral mucosal blood flow which was reduced by pretreatment with indomethacin. Systemic blood pressure, respiration and the pressor responses induced by catecholamines and gastric secretagogues were not affected by MN-1695. These results suggest that MN-1695 may possess selective effects on the gastric mucosal microcirculation and that suppressive effects of MN-1695 on the GMBF decrease induced by ulcerogenic stimuli may be responsible for its anti-ulcer activities in various types of experimental gastric ulcers.