tetragastrin and tiotidine

The histamine H2-receptor antagonistic activity and antisecretory effects of KU-1257 (N-ethyl-N'-[3-[3-(piperidinomethyl) phenoxy]propyl]urea, CAS 120958-90-9) were studied. The Ki values of KU-1257, roxatidine acetate, famotidine and cimetidine for the inhibition of [3H]-tiotidine binding to guinea-pig cerebral cortex were 0.040, 0.13, 0.016 and 0.40 mumol/l, respectively. The KB values of KU-1257, roxatidine acetate, famotidine and cimetidine for the antagonism against histamine-induced positive chronotropic response of isolated guinea-pig right atrium were 0.041, 0.14, 0.031 and 0.51 mumol/l, respectively. In pylorus-ligated rats, KU-1257, roxatidine acetate and famotidine inhibited gastric acid secretion with respective intraduodenal ID50 values of 12.3, 18.5 and 0.45 mg/kg. In dogs with Heidenhain pouch, the ID50 values of KU-1257 for the inhibition of acid output stimulated by histamine, tetragastrin and meat meal were 0.08, 0.39 and 0.15 mg/kg p.o., respectively. KU-1257 was 2-3 times more potent than roxatidine acetate regardless of secretagogues and twice less than famotidine in meat meal stimulation. These results indicate that KU-1257 is a potent and competitive histamine H2-receptor antagonist.

Topics: Animals; Cerebral Cortex; Cimetidine; Dogs; Famotidine; Food; Gastric Acid; Guinea Pigs; Heart Atria; Heart Rate; Histamine H2 Antagonists; In Vitro Techniques; Kinetics; Male; Phenylurea Compounds; Piperidines; Pylorus; Rats; Rats, Wistar; Tetragastrin