TACR1 and glioblastoma: EUC-001 exhibits a high affinity for the human receptor, with a Ki of 5.75 × 10−10 M. In vitro functional assays involving human glioblastoma (U373MG) cells, which endogenously express the NK1R, indicated that EUC-001 had no agonist activity, but that it was a potent antagonist of the receptor, inhibiting the [Sar9, Met(O2)11]-SP-induced response, with an IC50 of 6.9 × 10−10 M. EUC-001 also exhibited potent antagonist activity in vivo, as evidenced by its ability to inhibit the GR73632-induced foot-tapping response in gerbils.