Dissimilarities between methylene blue and cyanide on relaxation and cyclic GMP formation in endothelium-intact intrapulmonary artery caused by nitrogen oxide-containing vasodilators and acetylcholine
The objective of the present study was to ascertain whether cyanide shares the properties of methylene blue as a selective inhibitor of vascular smooth muscle relaxation elicited by agents that stimulate the formation of cyclic GMP. Experiments were performed with endothelium-intact rings prepared from bovine intrapulmonary artery. Methylene blue, a good inhibitor of soluble guanylate cyclase, antagonized both arterial relaxation and cyclic GMP accumulation in response to sodium nitroprusside, glyceryl trinitrate, S-nitroso-N-acetylpenicillamine and acetylcholine. In contrast, cyanide inhibited only the responses to sodium nitroprusside. Increasing concentrations of methylene blue depressed resting arterial levels of cyclic GMP and caused slowly developing but marked contractions whereas cyanide was without effect. Contractile responses to phenylephrine, potassium and U46619 were potentiated by methylene blue but not by cyanide. Preincubation of dilute solutions of cyanide containing sodium nitroprusside in oxygenated Krebs' buffer at 37 degrees C for 15 min before addition to bath chambers depressed relaxation and cyclic GMP accumulation caused by sodium nitroprusside markedly. Similar treatment of glyceryl trinitrate, however, failed to alter its effects in arterial rings. A chemical inactivation of sodium nitroprusside by cyanide appears to account for the specific inhibitory action of cyanide on arterial responses to sodium nitroprusside. This study indicates clearly that cyanide does not share the properties of methylene blue as an inhibitor of arterial relaxation elicited by vasodilators that stimulate cyclic GMP formation.
- Research Organization:
- Tulane Univ. School of Medicine, New Orleans, LA
- OSTI ID:
- 5575501
- Journal Information:
- J. Pharmacol. Exp. Ther.; (United States), Vol. 1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CYANIDES
BIOLOGICAL EFFECTS
METHYLENE BLUE
ACETYLCHOLINE
ARTERIES
CATTLE
COMPARATIVE EVALUATIONS
ENDOTHELIUM
GUANOSINE
IN VITRO
INHIBITION
MUSCLES
NITROGEN OXIDES
PHOSPHATES
VASODILATION
AMINES
AMMONIUM COMPOUNDS
ANIMAL TISSUES
ANIMALS
ANTI-INFECTIVE AGENTS
ANTIMICROBIAL AGENTS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
AZAARENES
AZINES
BLOOD VESSELS
BODY
CARDIOVASCULAR SYSTEM
CHALCOGENIDES
CHLORIDES
CHLORINE COMPOUNDS
DOMESTIC ANIMALS
DRUGS
ESTERS
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
MAMMALS
NEUROREGULATORS
NITROGEN COMPOUNDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
PARASYMPATHOMIMETICS
PHENOTHIAZINES
PHOSPHORUS COMPOUNDS
PURINES
QUATERNARY COMPOUNDS
RIBOSIDES
RUMINANTS
TISSUES
VERTEBRATES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)