Shows reduced activity vasopressin-oxytocin related receptors. Is active on fish receptors, but not on their human counterpart, supporting an evolved role of this conopressin in the envenomation process. Shows weak agonist activity on the zebrafish vasopressin-2 receptor (V2R) (EC(50)=1.72 uM). Has no effect on all other receptors tested. Expressed by the venom duct. The cysteine framework is C-C. It is unsure whether Ser-9 is amidated or not, it is why the two forms have been synthesized. The non-amidated form shows a weaker agonist activity on the zebrafish vasopressin-2 receptor (V2R) (EC(50)=3.6 uM). The state of the C-terminal residue does not impact its 3D-structure. Belongs to the vasopressin/oxytocin family.