Characterization of (5Z)-7-[3-endo-[(4-iodophenylsulfonyl) amino]-bicyclo[2.2.1]hep-2-exo-yl]heptenoic acid (IS-145) as an antagonist for the study of thromboxane A2 receptor

W. M. Kan, H. H. Tai

Research output: Contribution to journalArticle

Abstract

(5Z)-7-[3-endo-[(4-iodophenylsulfonyl) amino]bicyclo[2.2.1]-hep-2-exo-yl] heptenoic acid (IS-145) was characterized on its suitability for the study of thromboxane A2 (TXA2) receptor. Both the I-125 and I-127 analogs are very potent TXA2 antagonist. The I-127 analog interacted with the receptor specifically as shown by the displacement of [3H]-SQ29548 from its binding sites on human platelet membranes in a dose dependent manner. It also elicited specific biological responses by inhibiting I-BOP induced platelet aggregation. However, they failed to inhibit those induced by platelet activating factor. Moreover, it interfered with the TXA2 receptor activated signal transduction system by inhibiting I-BOP induced increase in GTP-γ-[35S] binding and GTPase activity. These data indicated that IS-145 was indeed a specific antagonist. The I-125 analog was used as a radioactive ligand to characterize TXA2 receptor in human platelet membranes. The binding was found to be saturable, reversible and specific with a KD of 5.8 nM and a Bmax of 1.9 pmol/mg protein.

Original languageEnglish
Pages (from-to)439-445
Number of pages7
JournalProstaglandins, Leukotrienes and Essential Fatty Acids
Volume48
Issue number6
DOIs
Publication statusPublished - 1993 Jun

All Science Journal Classification (ASJC) codes

  • Clinical Biochemistry
  • Cell Biology

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