Premium
Methylene blue but not changes in cyclic GMP inhibits resting and bradykinin‐stimulated production of prostacyclin by pig aortic endothelial cells
Author(s) -
Martin William,
Drazan Kveta M.,
Newby Andrew C.
Publication year - 1989
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.1476-5381.1989.tb11922.x
Subject(s) - bradykinin , prostacyclin , medicine , endocrinology , methylene blue , chemistry , alpha (finance) , stimulation , arachidonic acid , cyclic guanosine monophosphate , guanosine , biology , biochemistry , nitric oxide , receptor , enzyme , photocatalysis , catalysis , construct validity , nursing , patient satisfaction
1 Primary cultures of pig aortic endothelial cells produced 6‐keto‐prostaglandin F 1α (6‐keto PGF 1α ), the stable breakdown product of prostacyclin, both in the resting state and in response to bradykinin. The rise in 6‐keto‐PGF 1α production induced by bradykinin (1–100 n m ) was concentration‐dependent. 2 Treating endothelial cells with the inhibitor of soluble guanylate cyclase, methylene blue (0.1–20 μ m ) produced an irreversible reduction in resting and bradykinin (0.1 μ m )‐stimulated production of 6‐keto‐PGF 1α with an IC 50 of 0.5 ± 0.1 μ m . Treating endothelial cells with haemoglobin (10 μ m ) had no effect on resting or bradykinin (0.1 μ m )‐stimulated production of 6‐keto‐PGF 1α . 3 Two stimuli that elevate the level of guanosine 3′:5′‐cyclic monophosphate (cyclic GMP) in endothelial cells, 8‐bromo cyclic GMP (30 μ m ) and atriopeptin II (0.1 μ m ), each had no effect on resting or bradykinin (0.1 μ m )‐stimulated production of 6‐keto‐PGF 1α . Furthermore, treating endothelial cells with either 8‐bromo cyclic GMP (30 μ m ) or atriopeptin II (0.1 μ m ) had no effect on the ability of methylene blue (20 μ m ) to inhibit resting or bradykinin (0.1 μ m )‐stimulated production of 6‐keto‐PGF 1α . 4 Adding arachidonic acid (1 μ m ) to endothelial cells led to a marked stimulation of 6‐keto‐PGF 1α production. Treating cells with either methylene blue (20 μ m ) or the cyclo‐oxygenase inhibitor, flurbiprofen (10 μ m ), inhibited both resting and arachidonic acid (1 μ m )‐induced production of 6‐keto‐PGF 1α . 5 In pig aortic endothelial cells methylene blue appears to block prostacyclin production by a mechanism independent of inhibition of soluble guanylate cyclase. Care should be exercised when using methylene blue as a selective inhibitor of endothelium‐derived relaxing factor due to its additional ability to block production of the other endothelium‐derived vasodilator, prostacyclin.