Introduction: There is increasing evidence that a decrease in bladder blood flow (BBF) can cause the detrusor overactivity (DO) in human or animals. We investigated the effects of alpha1-adrenoceptor antagonist silodosin or phosphodiesterase type 5 inhibitor tadalafil on DO and BBF in the spontaneously hypertensive rats (SHR).
Methods: Twelve-week-old male SHRs were perorally administered with silodosin (100μg/kg), tadalafil (2 or 10 mg/kg) or vehicle once daily six weeks. Then, blood pressure (BP), urodynamic parameters and BBF were measured. Wistar rats were used as normotensive controls.
Results: SHRs showed significant increases in BP and micturition frequency (MF), and decreases in intercontraction interval (ICI) and BBF compare to the Wistar rats. Chronic treatment with silodosin or a higher dose of tadalafil (Tad10) ameliorated the MF, ICI and BBF in the SHRs. However, each drug failed to affect BP in the SHRs. And, there is no significant differences on these values between silodosin treated group and Tad10 treated group.
Conclusions: Silodosin or tadalafil ameliorated the hypertension related DO in the SHR via an increase in BBF.