3-Amino-5,6,7,8-tetrahydro-2-{4-[4-(quinolin-2-yl)piperazin-1-yl]butyl}quinazolin-4(3H)-one (TZB-30878) is a novel compound with both 5-hydroxytryptamine (5-HT) 1A agonism and 5-HT 3 antagonism effects. We hypothesized that TZB-30878 might have benefits from these dual effects as a medication for diarrhea-predominant irritable bowel syndrome (d-IBS), and these studies were designed to confirm the pharmacological properties of TZB-30878 and its efficacy in an IBS-like animal model. The binding assays demonstrated that [ 3 H]TZB-30878 selectively binds to human 5-HT 1A and 5-HT 3 receptors, with K d values of 0.68 Ϯ 0.03 and 8.90 Ϯ 1.73 nM, respectively. Systemic administration of TZB-30878 inhibited 5-HT-induced bradycardia in a dose-dependent manner in rats. In behavioral assays TZB-30878 produced signs of 5-HT syndrome in rats. These results suggest that TZB-30878 has dual effects as a 5-HT 1A receptor agonist and a 5-HT 3 receptor antagonist. Finally, we evaluated the effects of TZB-30878 on wrap restraint stress-induced defecation in an IBS-like model in rats. TZB-30878 (1-10 mg/kg p.o.) normalized stress-induced defecation in a dose-dependent manner, whereas the 5-HT 1A agonist tandospirone (30 and 100 mg/kg p.o.) and the 5-HT 3 antagonist alosetron (1-10 mg/kg p.o.) did not show such effects. Furthermore, this efficacy of TZB-30878 was partly antagonized by a 5-HT 1A antagonist, [O-methyl-3H]-N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide trihydrochloride (WAY-100635). These results suggest that 5-HT 1A receptor agonism and 5-HT 3 receptor antagonism contribute to the efficacy of TZB-30878 in the IBS-like model. The efficacy of TZB-30878 supports the concept that the presence of both actions, namely 5-HT 1A receptor agonism and 5-HT 3 receptor antagonism, could be an important mechanism in the treatment of d-IBS.
We have prepared a series of piperazinylpyridine derivatives for the treatment of irritable bowel syndrome (IBS). These compounds, which were designed by pharmacophore analysis, bind to both serotonin subtype 1A (5-HT1A) and subtype 3 (5-HT3) receptors. The nitrogen atom of the isoquinoline, a methoxy group and piperazine were essential to the pharmacophore for binding to these receptors. We also synthesized furo- and thienopyridine derivatives according to structure-activity relationship analyses. Compound 17c (TZB-20810) had high affinities to these receptors and exhibited 5-HT1A agonistic activity and 5-HT3 antagonistic activity concurrently, and is a promising drug for further development in the treatment of IBS.
We have prepared a series of quinazolinone derivatives linked with piperazinylquinoline for the treatment of irritable bowel syndrome (IBS). Using pharmacophore analysis, we designed and synthesized compounds which bind to both serotonin receptor subtype 1A (5-HT(1A)) and subtype 3 (5-HT(3)). Quinazolinone derivatives with a sulfur atom in the linker showed high affinity in in vitro assays, but low in vivo activity. Focusing on the linker to improve the pharmacokinetic profile, the sulfur atom in the linker was replaced with a methylene group. Further optimization led to the discovery of compound 17m (TZB-30878) ( J. Pharmacol. Exp. Ther. 2007 , 322 , 1315 - 1323 , Patent WO2005082887 (A1), 2005 ), a novel 5-HT(1A) agonist/5-HT(3) antagonist in the 3-aminoquinazolinone series. In in vivo functional assays, 17m dose dependently inhibited the Bezold-Jarisch reflex and induced 5-HT(1A)-mediated behaviors, and in an IBS animal model, 17m significantly inhibited stress-induced defecation. Pretreatment by WAY-100635 (5-HT(1A) antagonist) significantly attenuated but did not abolish the inhibitory effects of 17m. These results suggested that 17m exerted inhibitory effects via both 5-HT(1A) agonistic and 5-HT(3) antagonistic activities and that 17m would be useful as a therapeutic agent for IBS.
Receptor binding activity X 0280Design and Synthesis of Piperazinylpyridine Derivatives as Novel 5-HT1A Agonists/5-HT 3 Antagonists for the Treatment of Irritable Bowel Syndrome (IBS).-Among this novel synthesized, compounds such as (I) and (II) the derivative (Ib), named TZB-20810, is a promising candidate for further development in the treatment of IBS. The biological results are discussed in detail. -(ASAGARASU*, A.; MATSUI, T.; HAYASHI, H.; TAMAOKI, S.; YAMAUCHI, Y.; SATO, M.; Chem.
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