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Type: Artigo de periódico
Title: In Vivo Effects Of The Controlled No Donor/scavenger Ruthenium Cyclam Complexes On Blood Pressure.
Author: Marcondes, Fabiana G
Ferro, Alessander A
Souza-Torsoni, Adriana
Sumitani, Marie
Clarke, Michael J
Franco, Douglas W
Tfouni, Elia
Krieger, Marta H
Abstract: Ruthenium(II/III) complexes able to bind and release NO* were tested in vivo, in conscious Wistar rats instrumented for continuous blood pressure (BP) measurement and administration of in bolus injections (5 to 100 nmol/Kg i.v.) of trans-[Ru(II)Cl(NO+)(cyclam)](PF6)2 (cyclam-NO) or sodium nitroprusside (SNP). For normotensive rats, cyclam-NO produced a sustained 10% BP reduction of basal MAP during 7 +/- 0.4 to 11 +/- 0.3 min. In acute hypertensive rats, cyclam-NO produced BP reduction 3-fold larger than in normotensive rats and similar to that of SNP (maximal effect: 41 +/- 1.3 vs. 45 +/- 2.2 mmHg, respectively). However, the duration of the effect of cyclam-NO was 13 to 21-fold longer than that of SNP. The hypotensive effect of cyclam-NO was fully blocked in presence of continuous infusion of a NO* scavenger, carboxy-PTIO (6 mmol/Kg/min), or of the inhibitor of cGMP activation, methylene blue (83 nmol/Kg/min), or of the cyclam-NO precursor, trans-[RuCl(tfins)(cyclam)](tfms) (cyclam-tfms) (500 mmol/Kg/min). The long lasting BP reduction of cyclam-NO can be interpreted in terms of a slower rate of NO* release (k-NO = 2.2 x 10(-3) S(-1) at 35 degrees C) following chemical reduction (E(0') = 0.10 V vs NHE). In summary, cyclam-NO showed an hypotensive effect around 20 times longer than SNP in either normotensive or hypertensive rats, which was completely inhibited by methylene blue or carboxy-PTIO. Continuous infusion of cyclam-tfms completely blocked the hypotensive effect of cyclam-NO by scavenging the NO* released by the reduced cyclam-NO.
Subject: Animals
Blood Pressure
Cell Division
Cyclic N-oxides
Free Radical Scavengers
Heterocyclic Compounds
Methylene Blue
Ng-nitroarginine Methyl Ester
Nitric Oxide
Rats, Wistar
Citation: Life Sciences. v. 70, n. 23, p. 2735-52, 2002-Apr.
Rights: fechado
Date Issue: 2002
Appears in Collections:Unicamp - Artigos e Outros Documentos

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