Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/197830
Type: Artigo de periódico
Title: Vardenafil, But Not Sildenafil Or Tadalafil, Has Calcium-channel Blocking Activity In Rabbit Isolated Pulmonary Artery And Human Washed Platelets.
Author: Toque, H A
Teixeira, C E
Priviero, F B M
Morganti, R P
Antunes, E
De Nucci, G
Abstract: Phosphodiesterase type-5 (PDE5) inhibitors constitute a novel and important therapeutic option for the treatment of pulmonary hypertension. The effects of the PDE5 inhibitors sildenafil, tadalafil and vardenafil on rabbit isolated pulmonary artery ring preparations and on intracellular Ca2+ concentration of thrombin-stimulated human platelets were investigated. Rabbit pulmonary artery rings were mounted in 10 mL organ bath containing Krebs solution. Tissues were connected to force-displacement transducers, and changes in isometric force were recorded. Ca2+ flux in human washed platelets was measured. Sildenafil, tadalafil and vardenafil (0.0001-10 microM) concentration-dependently relaxed endothelium-intact and endothelium-denuded pulmonary artery rings. Endothelium denudation caused rightward shifts in the concentration-response curves to sildenafil, tadalafil and vardenafil (9-, 12- and 123-fold, respectively). Incubation with N(omega)-nitro-L-arginine methyl ester (100 microM) or ODQ (1H-[1,2,4] oxadiazolo [4,3,-a]quinoxalin-1-one) (10 microM) caused similar reductions of PDE5-induced vasorelaxations in intact rings. Sildenafil and tadalafil did not affect the phenylephrine-induced contractions, whereas vardenafil reduced the maximal responses, and shifted the phenylephrine-induced contraction curves to the right in endothelium-denuded rings (5- and 19-fold for 1 and 10 microM, respectively). Vardenafil (but neither sildenafil nor tadalafil) caused a marked rightward shift and a decrease of maximal contractile response to CaCl2. Vardenafil, but neither sildenafil nor tadalafil, significantly reduced the Ca2+ mobilization and Ca2+ influx in thrombin-stimulated washed platelets. Our results indicate that vardenafil, in contrast to sildenafil or tadalafil, also blocked Ca2+ fluxes, thus enhancing its vasorelaxation of the pulmonary artery.
Subject: Animals
Blood Platelets
Calcium
Calcium Channel Blockers
Calcium Channels
Carbolines
Dose-response Relationship, Drug
Endothelium, Vascular
Humans
Imidazoles
In Vitro Techniques
Male
Phosphodiesterase Inhibitors
Piperazines
Pulmonary Artery
Purines
Rabbits
Sulfones
Triazines
Vasodilation
Rights: fechado
Identifier DOI: 10.1038/bjp.2008.141
Address: http://www.ncbi.nlm.nih.gov/pubmed/18536732
Date Issue: 2008
Appears in Collections:Unicamp - Artigos e Outros Documentos

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