(D-Arg8)-Inotocin
(D-Arg8)-Inotocin is a potent, selective and competitive antagonist of vasopressin receptor (V1aR), with a Ki of 1.3 nM. (D-Arg8)-Inotocin shows more than 3000-fold selectivity for the human V1aR over the other three subtypes, OTR, V1bR and V2R.