Interacts with high affinity with vasopressin V1b receptor (AVPR1B) (Ki=8.3 nM), although the displacement of specific [3H]vasopressin binding is incomplete (a 30-40% resistant component remained). Has weaker affinity binding for oxytocin receptor (OXTR) (Ki=175 nM), and V1a receptor (AVPR1A) (Ki=827 nM). Expressed by the venom duct. The cysteine framework is C-C. Does not interact with V2R (up to 10 uM). Belongs to the vasopressin/oxytocin family.