A potent and highly selective 5-HT4 partial agonist, with pKi values of 8.7 at 5-HT4 sites in guinea pig striatum and > 6 at various other receptors, including 5-HT1A, 1D, 2A, 2C, D1, D2 and M1-3. Active in vivo, with an intrinsic activity relative to 5-HT of 0.5.