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Vaso‐reactivity of isolated bovine intra‐mammary artery to endogenous prostanoids and nitric oxide
Author(s) -
TRAKRANRUNGSIE N.,
WILL J. A.
Publication year - 1997
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/j.1365-2885.1997.tb00097.x
Subject(s) - nitric oxide , endogeny , chemistry , pharmacology , reactivity (psychology) , biochemistry , medicine , organic chemistry , pathology , alternative medicine
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, Nω‐Nitro L‐Arginine (L‐NNA: 3 x 10 −4 M) were determined during agonistmediated 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.