title: Involvement of COX-1 in A3 adenosine receptor-mediated contraction through endothelium in mice aorta.
abstract: We investigated whether A(3) adenosine receptor (A(3)AR) is involved in endothelium-mediated contraction through cyclooxygenases (COXs) with the use of wild-type (WT) and A(3) knockout (A(3)KO) mice aorta. A(3)AR-selective agonist, Cl-IBMECA, produced a concentration-dependent contraction (EC(50): 2.9 +/- 0.2 x 10(-9) M) in WT mouse aorta with intact endothelium (+E) and negligible effects in A(3)KO +E aorta. At 10(-7) M, contractions produced by Cl-IBMECA were 29% in WT +E, while being insignificant in A(3)KO +E aorta. Cl-IBMECA-induced responses were abolished in endothelium-denuded tissues (-E), in both WT and A(3)KO aorta. A(3)AR gene and protein expression were reduced by 74 and 72% (P < 0.05), respectively, in WT -E compared with WT +E aorta, while being undetected in A(3)KO +E/-E aorta. Indomethacin (nonspecific COXs blocker, 10(-5) M), SC-560 (specific COX-1 blocker, 10(-8) M), SQ 29549 (thromboxane prostanoid receptor antagonist, 10(-6) M), and furegrelate (thromboxane synthase inhibitor, 10(-5) M) inhibited Cl-IBMECA-induced contraction significantly. Cl-IBMECA-induced thromboxane B(2) production was also attenuated significantly by indomethacin, SC-560, and furegrelate in WT +E aorta, while having negligible effects in A(3)KO +E aorta. NS-398 (specific COX-2 blocker) produced negligible inhibition of Cl-IBMECA-induced contraction in both WT +E and A(3)KO +E aorta. Cl-IBMECA-induced increase in COX-1 and thromboxane prostanoid receptor expression were significantly inhibited by MRS1523, a specific A(3)AR antagonist in WT +E aorta. Expression of both A(3)AR and COX-1 was located mostly on endothelium of WT and A(3)KO +E aorta. These results demonstrate for the first time the involvement of COX-1 pathway in A(3)AR-mediated contraction via endothelium.
authors.affiliation: Department of Physiology & Pharmacology, Center for Interdisciplinary Research in Cardiovascular Sciences, Robert C. Byrd Health Science Center, West Virginia University, Morgantown, WV 26505, USA.
authors.forename: Habib R
authors.initials: HR
authors.lastname: Ansari
authors.forename: Ahmed
authors.initials: A
authors.lastname: Nadeem
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Tilley
authors.forename: S Jamal
authors.initials: SJ
authors.lastname: Mustafa
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D001572:Benzofurans / Q000494:pharmacology; D015153:Blotting, Western; D051545:Cyclooxygenase 1 / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D007213:Indomethacin / Q000494:pharmacology; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D009578:Nitrobenzenes / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D011720:Pyrazoles / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D043684:Receptor, Adenosine A3 / Q000172:deficiency / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D017482:Receptors, Thromboxane / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D013929:Thromboxane B2 / Q000378:metabolism; D013930:Thromboxane-A Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: C419146:2,3-diethyl-4,5-dipropyl-6-phenylpyridine-3-thiocarboxylate-5-carboxylate; D001572:Benzofurans; D016861:Cyclooxygenase Inhibitors; D008565:Membrane Proteins; D009578:Nitrobenzenes; D011720:Pyrazoles; D011725:Pyridines; D012333:RNA, Messenger; D043684:Receptor, Adenosine A3; D017482:Receptors, Thromboxane; C115461:SC 560; D013449:Sulfonamides; D014662:Vasoconstrictor Agents; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D013929:Thromboxane B2; D051545:Cyclooxygenase 1; C496512:Ptgs1 protein, mouse; D013930:Thromboxane-A Synthase; D000241:Adenosine; C039936:furegrelate; D007213:Indomethacin; C090034:2-chloro-N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide