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Updated: Jun 23, 2026
Bladder Smooth Muscle Strip Contractility as a Method to Evaluate Lower Urinary Tract Pharmacology
Published on: August 18, 2014
Chronic treatment with a PDE5 inhibitor increases contractile force of normal bladder in rats
Seiji Matsumoto1, Tadashi Hanai, Hirotsugu Uemura
1Urological and Urodynamic Center, Koushinkai Hospital, Toyoda, Sakai, Osaka, 590-0106, Japan. seiji_matsumoto@e-hainyo.com
Objectives:
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.
Materials And 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.
Conclusion:
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.
Insights
Vardenafil, a PDE5 inhibitor, enhances normal rat bladder contractile force. This suggests vardenafil
Area of Science:
- Pharmacology
- Urology
- Physiology
Background:
- Phosphodiesterase 5 (PDE5) inhibitors, like vardenafil, have demonstrated bladder protective effects in bladder outlet obstruction (BOO) models.
- Previous research indicated vardenafil preserves contractile force in BOO rat bladders.
Purpose of the Study:
- To investigate the effects of vardenafil on normal rat bladder function.
- To explore the underlying mechanisms of vardenafil's action in a non-diseased state.
Main Methods:
- Twenty female Sprague-Dawley rats were divided into water-treated and vardenafil-treated groups.
- Vardenafil (8 mg/kg/day) was administered orally for four weeks.
- Bladder strips underwent isometric organ bath assay to assess contractile responses to electrical field stimulation (EFS), carbachol, and potassium chloride (KCl).
Main Results:
- Chronic vardenafil treatment did not alter body or bladder weight.
- Significant increases in contractile forces were observed in response to EFS, carbachol, and KCl in vardenafil-treated rats.
- These findings indicate enhanced bladder contractility following vardenafil administration.
Conclusions:
- Vardenafil's positive effects on bladder contractility extend to normal bladders, not just diseased states.
- The observed effects on carbachol response are consistent with previous findings in BOO rats.
- Chronic vardenafil treatment improves the contractile function of normal rat bladder strips.
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