title: Role of CYP epoxygenases in A2A AR-mediated relaxation using A2A AR-null and wild-type mice.
abstract: We hypothesized that A2A adenosine receptor (A2A AR) activation causes vasorelaxation through cytochrome P-450 (CYP) epoxygenases and endothelium-derived hyperpolarizing factors, whereas lack of A2A AR activation promotes vasoconstriction through Cyp4a in the mouse aorta. Adenosine 5'-N-ethylcarboxamide (NECA; 10(-6) M), an adenosine analog, caused relaxation in wild-type A2A AR (A2A AR+/+; +33.99 +/- 4.70%, P < 0.05) versus contraction in A2A AR knockout (A2A AR(-/-); -27.52 +/- 4.11%) mouse aortae. An A2A AR-specific antagonist (SCH-58261; 1 microM) changed the NECA (10(-6) M) relaxation response to contraction (-35.82 +/- 4.69%, P < 0.05) in A2A AR+/+ aortae, whereas no effect was noted in A2A AR(-/-) aortae. Significant contraction was seen in the absence of the endothelium in A2A AR+/+ (-2.58 +/- 2.25%) aortae compared with endothelium-intact aortae. An endothelial nitric oxide synthase inhibitor (N-nitro-L-arginine methyl ester; 100 microM) and a cyclooxygenase inhibitor (indomethacin; 10 microM) failed to block NECA-induced relaxation in A2A AR+/+ aortae. A selective inhibitor of CYP epoxygenases (methylsulfonyl-propargyloxyphenylhexanamide; 10 microM) changed NECA-mediated relaxation (-22.74 +/- 5.11% at 10(-6) M) and CGS-21680-mediated relaxation (-18.54 +/- 6.06% at 10(-6) M) to contraction in A2A AR+/+ aortae, whereas no response was noted in A2A AR(-/-) aortae. Furthermore, an epoxyeicosatrienoic acid (EET) antagonist [14,15-epoxyeicosa-5(Z)-enoic acid; 10 microM] was able to block NECA-induced relaxation in A2A AR+/+ aortae, whereas omega-hydroxylase inhibitors (10 microM dibromo-dodecenyl-methylsulfimide and 10 microM HET-0016) changed contraction into relaxation in A2A AR(-/-) aorta. Cyp2c29 protein was upregulated in A2A AR+/+ aortae, whereas Cyp4a was upregulated in A2A AR(-/-) aortae. Higher levels of dihydroxyeicosatrienoic acids (DHETs; 14,15-DHET, 11,12-DHET, and 8,9-DHET, P < 0.05) were found in A2A AR+/+ versus A2A AR(-/-) aortae. EET levels were not significantly different between A2A AR+/+ and A2A AR(-/-) aortae. It is concluded that CYP epoxygenases play an important role in A2A AR-mediated relaxation, and the deletion of the A2A AR leads to contraction through Cyp4a.
authors.affiliation: Department of Physiology and Pharmacology, Center for Interdisciplinary Research in Cardiovascular Sciences, West Virginia University, Morgantown, WV 26506, USA.
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Nayeem
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Poloyac
authors.forename: John R
authors.initials: JR
authors.lastname: Falck
authors.forename: Darryl C
authors.initials: DC
authors.lastname: Zeldin
authors.forename: Catherine
authors.initials: C
authors.lastname: Ledent
authors.forename: Dovenia S
authors.initials: DS
authors.lastname: Ponnoth
authors.forename: Habib R
authors.initials: HR
authors.lastname: Ansari
authors.forename: S Jamal
authors.initials: SJ
authors.lastname: Mustafa
mesh_terms: D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000494:pharmacology; D000577:Amides / Q000494:pharmacology; D000578:Amidines / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000201:enzymology*; D016718:Arachidonic Acid / Q000378:metabolism; D002853:Chromatography, Liquid; D042926:Cytochrome P-450 CYP4A / Q000037:antagonists & inhibitors / Q000378:metabolism*; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D000072467:Cytochrome P450 Family 2; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D010627:Phenethylamines / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology; D043705:Receptor, Adenosine A2A / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D053719:Tandem Mass Spectrometry; D014230:Triazoles / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: C494022:14,15-eicosa-5-enoic acid; C098657:5-amino-7-(2-phenylethyl)-2-(2-furyl)pyrazolo(4,3-e)-1,2,4-triazolo(1,5-c)pyrimidine; D000577:Amides; D000578:Amidines; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; C000708209:HET0016; C121756:N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide; D010627:Phenethylamines; D011743:Pyrimidines; D043705:Receptor, Adenosine A2A; D014230:Triazoles; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; D016718:Arachidonic Acid; D019830:Adenosine-5'-(N-ethylcarboxamide); D003577:Cytochrome P-450 Enzyme System; D019001:Nitric Oxide Synthase; C086292:Cyp2c29 protein, mouse; D000072467:Cytochrome P450 Family 2; D042926:Cytochrome P-450 CYP4A; D011451:Prostaglandin-Endoperoxide Synthases; D015126:8,11,14-Eicosatrienoic Acid; D000241:Adenosine; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin