Chronic treatment with a PDE5 inhibitor increases contractile force of normal bladder in rats.
OBJECTIVE
We have previously shown that a phosphodiesterase 5 (PDE5) inhibitor, vardenafil, possesses bladder protective effects in bladder outlet obstruction (BOO) rats by preserving contractile force. In this study, we examined the effects of vardenafil to obtain clues for further research elucidating the mechanism of action of vardenafil on rat normal bladder.


METHODS
In all, twenty 12-week-old female Sprague-Dawley rats were divided into two equal groups: group 1, water-treated rats; and group 2, vardenafil-treated rats. Vardenafil (8 mg/kg/day) was given by drinking water. Four weeks after, vardenafil was washed out by giving water for 24-48 h, and then bladder was excised and dissected into four longitudinal strips for isometric organ bath assay. Contractile profile of bladder strips to electrical field stimulation (EFS), carbachol, and potassium chloride (KCl) was investigated.


RESULTS
Vardenafil had no effect on body and bladder weight. Contractile forces to EFS, carbachol, and KCl were all increased significantly in group 2 by chronic vardenafil treatment.


CONCLUSIONS
These effects were consistent with those observed in BOO rats for carbachol response, suggesting that effects of vardenafil are not limited to diseased condition, but also apply in normal condition. Chronic treatment with vardenafil increased contractile force of rat normal bladder strips.
Matsumoto
Seiji
S
Urological and Urodynamic Center, Koushinkai Hospital, Toyoda, Sakai, Osaka, 590-0106, Japan. seiji_matsumoto@e-hainyo.com
Hanai
Tadashi
T
Uemura
Hirotsugu
H
D000818:Animals; D005260:Female; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects*; D058986:Phosphodiesterase 5 Inhibitors; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D010879:Piperazines / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013450:Sulfones / Q000008:administration & dosage / Q000494:pharmacology; D014227:Triazines / Q000008:administration & dosage / Q000494:pharmacology; D001743:Urinary Bladder / Q000187:drug effects* / Q000502:physiology*; D000069058:Vardenafil Dihydrochloride
D007093:Imidazoles; D058986:Phosphodiesterase 5 Inhibitors; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride