A neurotensin receptor antagonist (IC50s = 1.19, 0.32, and 3.96 nM for human recombinant NTS receptors expressed in CHO cells, HT-29 cells, and adult rat brain membranes, respectively); inhibits inositol phosphate formation in HT-29 cells (IC50 = 3.9 nM); inhibits the firing rate of rat ventral pallidum neurons (1 mg/kg, i.v.); inhibits neurotensin-induced turning behavior in mice (40-640 mg/kg) as well as other neurotensin-induced cellular and behavioral responses