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- Title
Characterization of the urinary bladder dysfunction in renovascular hypertensive rats.
- Authors
Ramos-Filho, Antonio C.S.; Mónica, Fabíola Z.T.; Franco-Penteado, Carla F.; Rojas-Moscoso, Julio A.; Báu, Fernando R.; Schenka, André A.; De Nucci, Gilberto; Antunes, Edson
- Abstract
Aims Association between arterial hypertension and urinary bladder dysfunction has been reported in humans and spontaneously hypertensive rats. However, no study exists evaluating the bladder dysfunction in conditions of renovascular hypertension. The purpose of this study was to characterize the bladder dysfunction in two kidney-one clip (2K-1C) hypertensive rats. Methods A silver clip was placed around the renal artery of male Wistar rats. After 8 weeks, cystometric study, concentration-response curves to contractile and relaxant agents, frequency-dependent contractions, histomorphometry, muscarinic M2/M3 mRNA expression and cyclic AMP measurements were performed. Results 2K-1C rats showed enhanced bladder volume, wall thickness and smooth muscle density. 2K-1C rats also exhibited increases in bladder capacity and non-void contractions, and decreases in the inter-contraction intervals. In isolated detrusor smooth muscle (DSM), contractions to carbachol and electrical-field stimulation (EFS) were significantly greater in 2K-1C rats. The Rho-kinase inhibitor Y27632 (10 µM) significantly reduced the carbachol-induced contractions in SHAM and 2K-1C rats, but DSM remained overactive in 2K-1C rats in presence of Y27632. Concentration-dependent contractions to the P2X receptor agonist α,β-methylene ATP, KCl and extracellular Ca2+ did not change between SHAM and 2K-1C groups. In 2K-1C rats, isoproterenol, metaproterenol and BRL 37-344 (non-selective, β2- and β3-selective adrenoceptor agonists, respectively) produced significantly lower relaxations and decreased cAMP levels, whereas relaxant responses to sodium nitroprusside and BAY 41-2272 remained unchanged. Muscarinic M3 mRNA expression receptors were higher in 2K-1C group. Conclusions Renovascular hypertensive rats exhibit bladder dysfunction that involves tissue remodeling and enhanced muscarinic M3-mediated contractions associated with reduced β-adrenoceptor-mediated signal transduction. Neurourol. Urodynam. 30:1392-1402, 2011. © 2011 Wiley-Liss, Inc.
- Publication
Neurourology & Urodynamics, 2011, Vol 30, Issue 7, p1392
- ISSN
0733-2467
- Publication type
Article
- DOI
10.1002/nau.21074