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Regulation of nitric oxide‐like activity by prostanoids in smooth muscle of the canine saphenous vein
Author(s) -
Illiano Stephane,
Marsault Robert,
Descombes JeanJacques,
Verbeuren Tony,
Vanhoutte Paul M.
Publication year - 1996
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1996.tb15199.x
Subject(s) - nitroarginine , nitric oxide , contraction (grammar) , omega n methylarginine , nitric oxide synthase , endothelium , prostaglandin , phenylephrine , medicine , endocrinology , vascular smooth muscle , chemistry , muscle contraction , anesthesia , smooth muscle , blood pressure
1 Organ bath experiments and measurements of prostanoids were performed to investigate the presence of nitric oxide synthase in venous smooth muscle and its interaction with cyclo‐oxygenase. 2 In rings of canine saphenous vein without endothelium, the inhibitor of cyclo‐oxygenase, indomethacin (10 μ m ), induced contraction. N G ‐nitro‐L‐arginine (100 μ m ) (L‐NOARG), an inhibitor of nitric oxide synthase did not affect the tone of rings of canine saphenous vein when administered alone. However, in the presence of indomethacin L‐NOARG (100 μ m ) induced further contraction. 3 Similar results were obtained in response to N G ‐monomethyl‐L‐arginine (L‐NMMA)(300 μ m or N G ‐nitro‐L‐arginine methylester (L‐NAME)(100 μ m ). 4 When rings of canine saphenous vein without endothelium were contracted with phenylephrine (1 μ m ) instead of indomethacin, neither L‐NOARG or L‐NMMA induced further contraction. 5 When rings of canine saphenous vein without endothelium were contracted with noradrenaline (0.3 μ m ) in the presence of indomethacin (10 μ m ) plus L‐NOARG (100 μ m ), a relaxation to L‐arginine was observed. Transient relaxations to superoxide dismutase (150 u ml −1 ) were observed in all rings. 6 When rings of saphenous vein without endothelium were incubated with lipopolysaccharide (LPS) (100 μg ml −1 ) or interleukin −1β (10 u ml −1 ) the concentration‐contraction curve to noradrenaline was not affected. 7 Rings without endothelium released prostaglandin E 2 and prostaglandin I 2 , as measured by radiommunoassay. The basal production was abolished by indomethacin and not affected by L‐NOARG. 8 These results suggest that when cyclo‐oxygenase is inhibited, a nitric oxide synthase activity is revealed in rings of canine saphenous vein without endothelium.