(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.
|Number of pages||7|
|Journal||Prostaglandins, Leukotrienes and Essential Fatty Acids|
|Publication status||Published - 1993 Jun|
All Science Journal Classification (ASJC) codes
- Clinical Biochemistry
- Cell Biology