Shows reduced activity on vasopressin-oxytocin related receptors. Is more active on fish receptors, than on their human counterpart, supporting an evolved role of this conopressin in the envenomation process. Shows weak agonist activity on the zebrafish vasopressin receptor 1Ab (V1a1R) (EC(50)=13.6 uM). Also has weaker agonist activity on the human vasopressin receptor AVPR1B (EC(50)=38.2 uM). Has no effect on all other receptors tested. Expressed by the venom duct. The cysteine framework is C-C. This synthetic peptide shows multiple conformations, possibly due to cis-trans isomerization. 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 very weak agonist activity on the zebrafish vasopressin receptor 1Ab (V1a1R) (EC(50)=117 uM). The state of the C-terminal residue does not impact its 3D-structure. Belongs to the vasopressin/oxytocin family.