Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/195112
Type: Artigo de periódico
Title: Characterization Of The Hypotensive Effect Of S-nitroso-n-acetylcysteine In Normotensive And Hypertensive Conscious Rats.
Author: Ricardo, Kelly Fabiane Santos
Shishido, Sílvia Mika
de Oliveira, Marcelo Ganzarolli
Krieger, Marta Helena
Abstract: S-Nitrosothiols (RSNOs) are potent vasodilators found naturally in vivo. A variety of synthetic RSNOs have been considered as potential nitric oxide (NO) donors for biomedical applications. We have characterized the hypotensive effect of the RSNO S-nitroso-N-acetylcysteine (SNAC) in normotensive and hypertensive conscious rats. SNAC reduced the medium arterial pressure in a dose-response manner in both normotensive and hypertensive animals. At the same doses (EC(50) of SNAC), SNAC showed a vasodilator effect in normotensive rats more potent and more prolonged than that of sodium nitroprusside (SNP). The hypotensive effect of SNAC was also more potent in methylene blue-treated rats, where the cGMP-dependent pathway had been blockaded. These data indicate that SNAC acts by both cGMP-dependent and cGMP-independent pathways. It was also shown that the thiol N-acetylcysteine (NAC) potentiates the action of SNP in hypertensive rats, pointing to the mediation of thiols in the vasodilator action of SNP in this condition. Such mediation may involve the formation of a more potent thiol complex with the nitroprusside anion or the transfer of NO to NAC, generating SNAC as a primary vasoactive species. The kinetic monitoring of the decomposition reactions of SNAC and SNP showed that both compounds are quite stable under the infusion conditions used. Therefore, their vasodilator action cannot be assigned to their breakdown with release of free NO in solution. As the two compounds are unlikely to cross the plasmalemma of smooth muscle cells, their actions are probably associated with the mediation of endogenous thiols in transnitrosation reactions.
Subject: Acetylcysteine
Animals
Blood Pressure
Cyclic Gmp
Dose-response Relationship, Drug
Drug Stability
Drug Synergism
Drug Therapy, Combination
Hypertension
Male
Rats
Rats, Wistar
Sulfhydryl Compounds
Vasodilation
Rights: fechado
Identifier DOI: 
Address: http://www.ncbi.nlm.nih.gov/pubmed/12175821
Date Issue: 2002
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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