title: Specific receptors for thromboxane A2 in cultured vascular smooth muscle cells of rat aorta.
abstract: The specific binding site for thromboxane A2 (TXA2) was studied in cultured vascular smooth muscle cells (VSMC) of the rat aorta. [3H]SQ29,548, a potent and selective TXA2 receptor antagonist, displayed high-affinity and specificity, as well as saturable and displaceable binding to rat VSMC in culture. Scatchard analysis of equilibrium binding at 24 degrees C revealed a single class of binding sites with a Kd of 1.7 nM and a Bmax of 8.0 fmol/10(6) cells. A series of TXA2 receptor antagonists completely suppressed [3H]SQ29,548 binding to rat VSMC, and the rank order of their inhibitory potencies (Ki) correlated well with the potencies for suppression of the U46619-induced contraction of rat thoracic aorta. These results suggest that specific binding sites for [3H]SQ29,548 represent the TXA2 receptor in rat VSMC.
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000818:Animals; D001011:Aorta; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002478:Cells, Cultured; D005231:Fatty Acids, Unsaturated; D006834:Hydrazines / Q000378:metabolism; D007700:Kinetics; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011982:Receptors, Prostaglandin / Q000187:drug effects / Q000378:metabolism*; D017482:Receptors, Thromboxane; D013928:Thromboxane A2 / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D005231:Fatty Acids, Unsaturated; D006834:Hydrazines; D011450:Prostaglandin Endoperoxides, Synthetic; D011982:Receptors, Prostaglandin; D017482:Receptors, Thromboxane; D013928:Thromboxane A2; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; C037869:ONO 11120; C045749:SQ 29548; C049855:ONO 3708