A potent agonist of the serotonin 4 receptor (5-HT4, Ki = 3.9-31 nM; also acts as an antagonist for the 5-HT2A, 5-HT2B, and 5-HT2C receptors (Ki = 32, 3.9, and 100 nM, respectively); stimulates colonic motility and transit in vivo.