The Serotonin 5-HT4 Receptor. 2. Structure-Activity Studies of the Indole Carbazimidamide Class of Agonists
作者:Karl-Heinz Buchheit、Rainer Gamse、Rudolf Giger、Daniel Hoyer、Francois Klein、Edgar Kloeppner、Hans-Juergen Pfannkuche、Henri Mattes
DOI:10.1021/jm00013a010
日期:1995.6
A number of substituted indole carbazimidamides were prepared and evaluated as 5-HT4 receptor agonists by using the isolated field-stimulated guinea pig ileum preparation. Their selectivity for the 5-HT4 receptor was established by examining their affinity for other 5-HT receptors using radioligand-binding techniques. Several selective and highly potent full as well as partial agonists emerged from this study. For example, 1b,d were found to be the most potent, full 5-HT4 receptor agonists described so far (EC(50) = 0.5 and 0.8 nM, respectively), being 6 and 4 times more potent than serotonin itself. On the other hand, 5b and 1h appeared as partial 5-HT4 receptor agonists in the nonstimulated guinea pig ileum preparation with potencies, evaluated against serotonin action, respectively similar (5b, K-i = 12 nM) to and 300-fold higher (1h, K-i = 0.04 nM) than serotonin.