Possible involvement of 5-HT4 receptors, in addition to 5-HT3 receptors, in the emesis induced by high-dose cisplatin in Suncus murinus.

To clarify the mechanism for the severe emesis concomitant with intensive chemotherapy, we investigated the effects of 5-HT3- and 5-HT4-receptor antagonists on the emesis induced by the high-dose of cisplatin in Suncus murinus. The emesis induced by 50 mg/kg of cisplatin was reduced by the oral pretreatment with tropisetron, which is known as a 5-HT3- and 5-HT4-receptor dual antagonist in vitro, with the ID50 value of 0.52 mg/kg.

The effect of zaldaride maleate, an antidiarrheal compound, on acetylcholine-induced intestinal electrolyte secretion.

The effect of zaldaride on acetylcholine-induced colonic electrolyte secretion was examined. The short-circuit current response to acetylcholine was partially reduced by tetrodotoxin, a neuronal blocker, and was completely inhibited by atropine, an acetylcholine M receptor antagonist, in the rat colonic preparations. The tetrodotoxin sensitive effect was significantly inhibited by zaldaride, whereas the tetrodotoxin insensitive effect was not affected.

Acceleration by KW-5092 of intestinal motility associated with acetylcholine release in vivo.

Effect of KW-5092 ([1-[2-[[[5-(piperidinomethyl)-2-furanyl]methyl]amino]ethyl]-2- imidazolidinylidene]propanedinitrile fumarate) on intestinal motility and release of endogenous acetylcholine (ACh) were measured simultaneously in the small intestine of anesthetized dog using the in vivo microdialysis method. Intraarterial and intravenous administrations of KW-5092 accelerated the intestinal motility and increased dialysate ACh concentrations. These KW-5092-induced responses paralleled the increase in blood concentration of KW-5092.

Synthesis of tricyclic compounds as steroid 5alpha-reductase inhibitors.

A series of 4-phenoxybutyric acid derivatives attached to a tricyclic skeleton were prepared and evaluated as 5alpha-reductase inhibitors. Structure activity relationships for these compounds in terms of rat epididymis (type 2) 5alpha-reductase inhibitory activities reveal that 1) the substitution pattern at the 11-position of dibenz[b,e]oxepin influenced potency, 2) higher lipophilicity of the tricyclic skeleton improved potency, whereas the existence of a basic nitrogen atom in this skeleton was detrimental to potency, and 3) isobutyl substitution at the 8 positon of the azepine skeleton was tolerated. Among the tricyclic compounds studied, 4-[3-[5-benzyl-8-(2-methyl)propyl-10,11-dihydrodibenz[b,f]azepine- 2-carboxamido]phenoxy]butyric acid (26) was the most potent inhibitor of rat type 2 5alpha-reductase at 0.

Indole and benzimidazole derivatives as steroid 5alpha-reductase inhibitors in the rat prostate.

A novel series of indole and benzimidazole derivatives were synthesized and evaluated for their inhibitory activity of rat prostatic 5alpha-reductase. Among these compounds, 4-¿2-[1-(4,4'-dipropylbenzhydryl)indole-5-carboxamido]phenoxy¿buty ric acid (15) and its benzimidazole analogue 25 showed potent inhibitory activities for rat prostatic 5alpha-reductase (IC50 values of 9.6+/-1.