text: Binding domains of the oxytocin receptor for the selective oxytocin receptor antagonist barusiban in comparison to the agonists oxytocin and carbetocin.
  We have analyzed binding domains of the oxytocin receptor for barusiban, a highly selective oxytocin receptor antagonist, in comparison to the combined vasopressin V1A/oxytocin receptor antagonist atosiban and the agonists oxytocin and carbetocin. For this purpose, chimeric 'gain-in function' oxytocin/vasopressin V2 receptors were expressed in COS-7 cells. These recombinant receptors have been produced by transfer of domains from the oxytocin receptor into the related vasopressin V2 receptor and have already been successfully employed for the identification of ligand binding domains at the oxytocin receptor (Postina, R., Kojro, E., Fahrenholz, F., 1996. Separate agonist and peptide antagonist binding sites of the oxytocin receptor defined by their transfer into the V2 vasopressin receptor. J. Biol. Chem. 271, 31593-31601). In displacement studies with 10 chimeric receptor constructs, the binding profile of barusiban was compared with the binding profiles of the ligands oxytocin, [Arg8]vasopressin, carbetocin, and atosiban. The binding profiles for the agonists oxytocin and carbetocin were found to be similar. For both agonists, important binding domains were the extracellular N-terminus (=E1) and the extracellular loops E2 and E3 from the oxytocin receptor. For the vasopressin V1A/oxytocin receptor antagonist atosiban, none of the receptor constructs were able to provide a binding with higher affinity than the starting vasopressin V2 receptor. In contrast, the binding of barusiban was significantly improved when the transmembrane domains 1 and 2 were transferred from the oxytocin receptor to the vasopressin V2 receptor. The binding domain of barusiban differs from the binding domain of the agonists and the nonselective oxytocin receptor antagonist d(CH2)5[Tyr-(Me)2,Thr4,Orn8,Tyr9]vasotocin that has been used in previous studies. Overall, the data supported the concept of a central pocket site within the oxytocin receptor.
entities.id: T10 T11 T12 T13 T14 T15 T16 T17 T18 T19 T1 T20 T21 T22 T23 T24 T25 T26 T27 T28 T29 T2 T30 T31 T32 T33 T34 T35 T36 T37 T38 T39 T3 T40 T41 T42 T43 T44 T45 T46 T47 T48 T49 T4 T50 T51 T52 T53 T54 T55 T56 T57 T58 T59 T5 T60 T61 T62 T6 T7 T8 T9
entities.type: CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL GENE-Y GENE-Y GENE-Y GENE-N GENE-Y GENE-N GENE-Y GENE-Y GENE-N GENE-Y CHEMICAL GENE-Y GENE-N GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y GENE-Y CHEMICAL GENE-Y GENE-Y GENE-Y CHEMICAL CHEMICAL CHEMICAL CHEMICAL
entities.text: vasopressin barusiban vasopressin oxytocin vasopressin barusiban oxytocin d(CH2)5[Tyr-(Me)2,Thr4,Orn8,Tyr9]vasotocin oxytocin atosiban carbetocin oxytocin carbetocin oxytocin vasopressin oxytocin oxytocin vasopressin oxytocin barusiban oxytocin atosiban vasopressin barusiban oxytocin oxytocin [Arg8]vasopressin oxytocin carbetocin oxytocin oxytocin barusiban oxytocin vasopressin oxytocin oxytocin receptor vasopressin V1A/oxytocin receptor vasopressin V2 receptor vasopressin V1A/oxytocin receptor vasopressin V2 receptor oxytocin receptor vasotocin oxytocin receptor carbetocin oxytocin oxytocin/vasopressin V2 receptors oxytocin receptor oxytocin receptor vasopressin V2 receptor oxytocin receptor oxytocin receptor V2 vasopressin receptor oxytocin receptor oxytocin N oxytocin oxytocin receptor oxytocin receptor oxytocin vasopressin oxytocin atosiban