A ligand for serotonin receptors, acting as an antagonist for 5-HT at 5-HT1 and 5-HT2 in rat cortical membranes with IC50 values of 6 and 1 nM, respectively; binds to the human 5-HT6 receptor with an affinity comparable to that of 5-HT (Kis = 120 and 100 nM, respectively).