Scyliorhinin II is a selective neurokinin-3 receptor agonist, with a K_i of 2.5 nM for neurokinin-3 receptor in rat cerebral cortex. IC50 & Target: Ki: 2.5 nM (Neurokinin-3 receptor)^[1] In Vitro: Scyliorhinin II is a neurokinin-3 selective tachykinin receptor, with a K_i of 2.5 nM for neurokinin-3 (NK-3) receptor in rat cerebral cortex. Scyliorhinin II has little effect on NK-1 and NK-2 receptors, with K_i (NK-1 receptor)/K_i (NK-3 receptor) and K_i (NK-2 receptor)/K_i (NK-3 receptor) of 176 and 200^[1]. In Vivo: Scyliorhinin II produces potent, dose-related reciprocal hindlimb scratching about equipotently with an ED₅₀ of 0.08 nmol via intracerebroventricularly (i.c.v.) administration in mice^[2].