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Involvement of nitric oxide in the endothelium‐dependent relaxation induced by hydrogen peroxide in the rabbit aorta
Author(s) -
Zembowicz Artur,
Hatchett Richard J.,
Jakubowski Andrzej M.,
Gryglewski Richard J.
Publication year - 1993
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.1476-5381.1993.tb13785.x
Subject(s) - nitric oxide , chemistry , endothelium , phenylephrine , endothelium derived relaxing factor , nitric oxide synthase , hydrogen peroxide , methylene blue , nitroarginine , aorta , vasodilation , stereochemistry , biophysics , biochemistry , endocrinology , medicine , biology , organic chemistry , photocatalysis , blood pressure , catalysis
1 The effects of hydrogen peroxide (H 2 O 2 , 0.1–1 m m ) on the tone of the rings of rabbit aorta precontracted with phenylephrine (0.2–0.3 μ m ) were studied. 2 H 2 O 2 induced a concentration‐dependent relaxation of both the intact and endothelium‐denuded rings. However, in the presence of intact endothelium, H 2 O 2 ‐induced responses were 2–3 fold larger than in its absence, demonstrating the existence of endothelium‐independent and endothelium‐dependent components of the vasorelaxant action of H 2 O 2 . 3 The endothelium‐dependent component of H 2 O 2 ‐induced relaxation was prevented by N G ‐nitro‐ l ‐arginine methyl ester ( l ‐NAME, 30 μ m ) or N G ‐monomethyl‐ l ‐arginine (300 μ m ), inhibitors of nitric oxide synthase (NOS), in a manner that was reversible by l ‐, but not by d ‐arginine (2 m m ). The inhibitors of NOS did not affect the responses of denuded rings. 4 Methylene blue (10 μ m ), an inhibitor of soluble guanylate cyclase, blocked H 2 O 2 ‐induced relaxation of both the intact and denuded rings. 5 H 2 O 2 (1 m m ) enhanced the efflux of cyclic GMP from both the endothelium‐intact and denuded rings. The effect of H 2 O 2 was 4 fold greater in the presence of intact endothelium and this endothelium‐dependent component was abolished after the inhibition of NOS by l ‐NAME (30 μ m ). 6 In contrast to the effects of H 2 O 2 , the vasorelaxant action of stable organic peroxides, tert ‐butyl hydroperoxide or cumene hydroperoxide, did not have an endothelium‐dependent component. Moreover, they did not potentiate the efflux of cyclic GMP from the rings of rabbit aorta. 7 Exogenous donors of NO, specifically, 3‐morpholinosydnonimine (SIN‐1), glyceryl trinitrate or sodium nitroprusside were used to decrease the tone of denuded rings to the level induced by endogenous NO released from intact endothelium. This procedure did not influence the vasorelaxant activity of H 2 O 2 , showing that H 2 O 2 does not potentiate the vasorelaxant action of NO within the smooth muscle. 8 Thus, H 2 O 2 ‐induced relaxation in the rabbit aorta has both endothelium‐dependent and independent components. The endothelium‐dependent component of the relaxant action of H 2 O 2 is due to enhanced endothelial synthesis of NO.