Vardenafil modulates bladder contractility through cGMP-mediated inhibition of RhoA/Rho kinase signaling pathway in spontaneously hypertensive rats

J Sex Med. 2009 Jun;6(6):1594-1608. doi: 10.1111/j.1743-6109.2009.01249.x. Epub 2009 Mar 30.


Introduction: Phosphodiesterase type 5 inhibitors (PDE5i), the most widely used drugs for erectile dysfunction, could also improve lower urinary tract symptoms, essentially due to overactive bladder (OAB), a condition hypothesized to be a result of an increased RhoA/Rho-kinase (ROCK) signaling. Phosphorylation/inactivation of RhoA by cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) activity has been described in vascular smooth muscle.

Aim: The aim of this paper was to investigate whether vardenafil-induced cGMP accumulation reduces RhoA/ROCK signaling in bladder.

Methods: Spontaneously hypertensive rats (SHRs), a strain genetically prone to develop OAB, were treated with vardenafil (10 mg/kg/day) for 2 weeks. Wistar-Kyoto rats (WKY) were used as control. In vitro experiments were performed in human bladder smooth muscle cells (hBCs).

Main outcome measures: Urodynamic parameters were registered in vivo in anesthetized WKY and SHRs. RhoA/ROCK activity in bladder was evaluated by molecular and functional studies in tissues and cells.

Results: The intercontraction interval and bladder capacity, and were decreased in SHRs and restored by vardenafil. The in vitro relaxant effect of the ROCK inhibitor Y-27632 was higher in bladder strips from SHR than from WKY and reduced by vardenafil. Nomega-nitro-L-arginine-methyl-ester (a NO-synthase inhibitor, 40 mg/kg/day during the last week of the 2-week treatment with vardenafil) partially antagonized vardenafil effect on Y-27632 responsiveness. Vardenafil prevented RhoA membrane translocation/activation, decreased ROCK activity, and increased cGMP levels in vivo (rat) and in vitro (hBCs). Exposing hBCs to vardenafil increased Ser(188) RhoA phosphorylation, to the same extent as the PDE5-insensitive PKG agonist Sp-8-Br-PET-cGMP. Moreover, vardenafil inhibited several RhoA-dependent functions in hBCs, including smooth muscle gene transcription and endothelin-1-induced migration. These effects were reverted by the PKG inhibitor KT 5823, further suggesting a cGMP/PKG-dependency. In hBCs, vardenafil was active in the low nanomolar range.

Conclusions: This is the first study demonstrating that the effect of vardenafil on OAB could be partially determined by a cGMP-dependent RhoA/ROCK signaling inhibition.

MeSH terms

  • Animals
  • Blotting, Western
  • Cyclic GMP / metabolism*
  • Hypertension / enzymology*
  • Hypertension / physiopathology*
  • Imidazoles / pharmacology*
  • Muscle Contraction / drug effects*
  • Muscle, Smooth / drug effects
  • Muscle, Smooth / enzymology
  • Phosphodiesterase 5 Inhibitors
  • Phosphodiesterase Inhibitors / pharmacology*
  • Piperazines / pharmacology*
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / drug effects*
  • Sulfones / pharmacology
  • Triazines / pharmacology
  • Urinary Bladder, Overactive / drug therapy*
  • Urodynamics / drug effects
  • Vardenafil Dihydrochloride
  • rho-Associated Kinases / drug effects*
  • rhoA GTP-Binding Protein / drug effects*


  • Imidazoles
  • Phosphodiesterase 5 Inhibitors
  • Phosphodiesterase Inhibitors
  • Piperazines
  • Sulfones
  • Triazines
  • Vardenafil Dihydrochloride
  • rho-Associated Kinases
  • rhoA GTP-Binding Protein
  • Cyclic GMP