Selective vasopressin V1A receptor antagonist. Inhibits vasopressin and oxytocin-induced increases in intracellular calcium concentrations in vitro (IC50 values are 5 and 30 nM respectively). Exhibits potent and prolonged antivasopressor activity and induces anxiolytic-like effects in the dorsal, but not ventral, hippocampus in vivo. MW (observed): 1151.38.