Effect of Tamsulosin on Bladder Blood Flow and Bladder Function in a Rat Model of Bladder Over Distention/Emptying Induced Bladder Overactivity

Abstract

Bladder over distention/emptying induced bladder blood flow decrease/partial recovery and caused bladder overactivity via a mechanism other than capsaicin sensitive C-fiber activation. Findings in tamsulosin treated rats confirmed the potency of tamsulosin to increase bladder blood flow and ameliorate bladder overactivity.

Are blood vessels a target to treat lower urinary tract dysfunction?

“…Along with the only partially restored perfusion, a shortening of micturition intervals was observed, which also was ameliorated by tamsulosin treatment, indicating that hypoperfusion affected bladder function. Of note, tamsulosin did not alter basal bladder blood flow in this model, indicating a lack of tonic activation of the involved α 1 -adrenoceptors in the bladder vasculature in healthy rats (Okutsu et al 2011).…”

Effect of a single treatment with tadalafil on blood flow in lower urinary tract tissues in rat models of bladder overdistension/emptying and abdominal aorta clamping/release

“…These findings indicate that bladder ischemia is a key mechanism underlying symptoms that are associated with BPH. Although the decreased BBF observed in our acute rat model may not reflect exactly the chronic decrease in BBF in human BPH, bladder O/E carried out under conditions similar to those of our model have been used by us and others to study the effect of drugs on BBF and bladder dysfunction (Kawai et al, 2013;Okutsu et al, 2011). Therefore, it is likely that tadalafil increased the blood supply and reduced the bladder ischemia caused by BOO.…”

“…This mode of action of tadalafil on BBF appears to be different from that of the α 1 -adrenoceptor antagonist tamsulosin. Thus, in a rat model of bladder O/E, continuous treatment for one week with tamsulosin produces a greater difference between the value of BBF observed during bladder overdistension (ischemia phase) and that observed during bladder emptying (reperfusion phase) than is observed in control groups (Mizuno et al, 2010;Okutsu et al, 2011). Tadalafil avoided this situation by promoting improved BBF during clamping as well as during the release phase.…”

Effects of Chronic Treatment With Cilostazol, a Phosphodiesterase 3 Inhibitor, on Female Rat Bladder in a Partial Bladder Outlet Obstruction Model

“…The evidence has suggested that bladder ischemia causes significant bladder dysfunction and leads to decreased contractile responses of the bladder.  1 -blocker has been shown to have a protective effect on bladder function of the rat after BOO or bladder overdistension possibly through an improvement of bladder ischemia [6,7]. In clinical practice, 1 -blocker is widely used as a first-line treatment for male patients with LUTS that are associated with BOO due to BPH (LUTS/BPH).…”

“…Increasing evidence has shown that ischemia and reperfusion are major etiologic factors in the progression of bladder dysfunction induced by BOO, and that part of the damage is due to the generation of free radicals and the resultant cellular and subcellular membrane peroxidation [1]. The importance of ischemia as an etiologic factor in bladder dysfunction has been supported by recent animal studies in which bladder ischemia was experimentally created by BOO, bladder overdistension and atherosclerosis [2][3][4][5][6][7]. The evidence has suggested that bladder ischemia causes significant bladder dysfunction and leads to decreased contractile responses of the bladder.…”