[CAS NO. 170729-80-3]  Aprepitant (MK-0869)

Aprepitant antagonizes the effects of substance P by binding to NK-1 receptors primarily in the CNS, but also in the periphery. Aprepitant, at concentrations of 0.1 nM displaces 50% of substance P from hNK1 receptors transfected in CHO or COS cells. In radioligand binding assays, Aprepitant is 3000-fold selective for the human cloned NK1 receptor versus the human cloned NK3 receptor and >50,000-fold selective over the human cloned NK2 receptor. In a range of assays at other human cloned G–protein coupled receptors, Aprepitant retains >50,000-fold selectivity for the human cloned NK1 receptor. Aprepitant is inactive in human monoamine oxidase A and B assays and at human serotonin 5–HT1A, 5–HT2A, 5–HT2c, 5–HT3, 5–HT5, 5–HT6, and 5–HT7 receptors (IC50>3 μM). In the PANLABS panel of radioligand binding screens using native animal tissues, Aprepitant inhibits [H]substance P binding to native NK1 receptors in rat submaxillary gland; there are no significant interactions of Aprepitant with any other native animal G–protein coupled receptors or ion channels examined in the PANLABS screen. Aprepitant is inactive in monoamine uptake site (NE, 5–HT, DA) counterscreens using human and animal tissues (IC50> 3 μM)