Vaso-reactivity of isolated bovine intra-mammary artery to endogenous prostanoids and nitric oxide.
The modulatory role of locally produced cyclooxygenase products and endothelium-derived nitric oxide in controlling vascular tone was investigated in bovine intra-mammary artery. Vascular reactivity initiated by vasoactive compounds, endothelin-1 (ET-1), bradykinin (BK), and substance P (SP) was measured isometrically in an isolated tissue bath. The effects of a cyclooxygenase inhibitor, indomethacin (10(-5) M) and an inhibitor of nitric oxide production, N omega-Nitro L-Arginine (L-NNA: 3 x 10(-4) M) were determined during agonist-mediated responses. Indomethacin alone markedly enhanced vascular contraction produced by ET-1, while L-NNA did not. Inhibition of endothelium-derived nitric oxide synthesis by L-NNA, however, significantly attenuated BK- and SP-induced vascular relaxations, whereas indomethacin had slight influence. The potentiation between indomethacin and L-NNA in regulating vasomotor tone was not observed in this vascular bed. Thus, it appeared that both the cyclooxygenase and endothelium-derived nitric oxide pathways participated in modifying vascular reactivity. Domination of one pathway over the other depended upon the agonist used to stimulate vascular tissue.
Trakranrungsie
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Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison 53706, USA.
Will
J A
JA
D000818:Animals; D001920:Bradykinin / Q000502:physiology; D002417:Cattle; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D004347:Drug Interactions; D019332:Endothelin-1 / Q000502:physiology; D005260:Female; D007213:Indomethacin / Q000494:pharmacology*; D008323:Mammary Arteries / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019335:Nitroarginine / Q000494:pharmacology*; D013373:Substance P / Q000502:physiology; D014661:Vasoconstriction / Q000502:physiology
D016861:Cyclooxygenase Inhibitors; D019332:Endothelin-1; D019335:Nitroarginine; D009569:Nitric Oxide; D013373:Substance P; D001920:Bradykinin; D007213:Indomethacin