Infravesical outlet obstruction in human is one of the most commonly observed condition in the urologic field and often related to voiding difficulty with unstable bladder. The ppathophysiological background for voiding difficulty is unknown and
also
difficult to investigate in human. We, herein, performed animal study to investigate whether and how short-term infravesical outlet obstruction does affect the function of rat bladder, and to estabilish the animal model with infravesical outlet
obstruction for further studies. Infravesical outlet obstruction was created by placing a silicon sleeve around the bladder neck and proximal urethra of mature female rats. At one week after operation, cystometrical evaluation and isolated
detrusor
strip study was performed in each rat. The whole bladder weight of obstructed group significantly increased to four times that of control group. In cystometrical investigations, obstructed group showed unstable bladder. Furthermore, the
obstructed
group
showed increased bladder capacity and residual urine volume, compared to those of control group. In isolated detrusor muscle strip study contractile responses of detrusor muscle to field stimulation, bethanechol and ATP were less prominent in
obstructed
group than in control group. However, tetrodotoxin could not completely abolish EFS-induced detrusor contraction in obstructed group, compared to that in control group. These results indicate that short-term obstructed bladder showed a
significant
decrease in detrusor contractility as well as abnormal detrusor contraction, which may be resulted from the degeneration of detrusor muscle, although neurogenic cause remains to be further investigated.
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