title: O2-sensitivity of beta adrenergic responsiveness in isolated bovine and porcine coronary arteries.
abstract: The relation between pO2 and beta adrenergic responsiveness was studied in isolated bovine and porcine coronary artery rings. Isoproterenol elicited a concentration-dependent relaxation of bovine and porcine coronary artery rings precontracted with KCI (2 X 10(-2) M) or histamine (10(-6) M); beta adrenergic responsiveness was significantly lower in K+-depolarized coronary arteries. A decrease of bath pO2 from 95 to 40% significantly reduced beta adrenergic responsiveness in both coronary preparations precontracted with either KCI or histamine. Similarly, exogenous arachidonic acid (3 X 10(-6) to 3 X 10(-5) M) depressed isoproterenol-induced relaxations in both tissues. Indomethacin (5 X 10(-6) M) augmented beta adrenergic responsiveness in the presence of 95% O2 and prevented the inhibitory effects of the decrease in bath pO2 and arachidonic acid in both preparations. The experimental data suggest that the demonstrated O2-sensitivity of beta adrenergic responsiveness is mediated by vascular prostaglandin synthesis in isolated large coronary arteries.
mesh_terms: D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D002417:Cattle; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D010100:Oxygen / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013552:Swine
chemical_list: D001095:Arachidonic Acids; D011943:Receptors, Adrenergic, beta; D016718:Arachidonic Acid; D006632:Histamine; D007545:Isoproterenol; D011188:Potassium; D010100:Oxygen; D007213:Indomethacin