Effect of Acute Complete Obstruction on the Rabbit Urinary Bladder

Abstract

Studies on the effect of partial bladder outlet obstruction demonstrate that significant alterations in urinary bladder structure and function occur within 24 hours of the creation of the obstruction. These studies suggest that many of the functional and structural alterations following partial outlet obstruction may result from the initial overdistension which occurs within the first 24 hours. In these present studies, we investigated the time course of the effect of complete obstruction of the rabbit urinary bladder on the contractile response to bethanechol and field stimulation and on the muscarinic receptor density. Male White New Zealand rabbits were divided into five groups: controls, four, eight, 20, and 24 hours of complete obstruction. The results demonstrated that there was a significant decrease in both the contractile response to muscarinic stimulation and muscarinic receptor density at four hours following outlet obstruction (at a time when there was no bladder overdistension). The receptor density and contractile response to stimulation further decreased over the 24 hour period. These studies indicate that the initial decrease in muscarinic receptor density and contractile response to muscarinic stimulation may be mediated in part by the high level of spontaneous contractile activity induced by ligation of the urethra.

Effects of ATP‐sensitive K+ channel openers and tolterodine on involuntary bladder contractions in a pig model of partial bladder outlet obstruction

“…Detrusor instability has been modeled by partial bladder outlet obstruction in several animal species, including rat [Malmgren et al, 1989], guinea pig [Mostwin et al, 1991], and rabbit [Kitada et al, 1989]. The partial obstruction of the pig urethra with a silver ring, initially described by Sibley [1985], resulted in hypertrophy of the bladder wall, partial denervation of the bladder, and spontaneous contractile activity [Sibley, 1987;Speakman et al, 1987;Dixon et al, 1989].…”

Experimental Hyperreflexia: Effect of Intravesical Administration of Various Agents

“…In addition, it occurs in the absence of any known dysfunction [3][4][5], Therapies for uninhibited contractions include oral drug therapy [6][7][8], instillation drug therapy [9,10] and chemical or surgical parasympa thetic nerve ablation [11,12], All therapies are directed at decreasing bladder contractile activity. In order to develop more effective therapies for uninhibited bladder contrac tions, we have developed an experimental model of reflex contractile activity (hyperre flexia) [13,14], Utilizing this model, we have compared the effectiveness of a variety of intravesically administered agents on hyper reflexia.…”

The effect of pregnancy and contractile activity on bladder muscarinic receptor subtypes

“…Furthermore, 4 hr of experimentally induced uninhibited bladder contractions decreases muscarinic receptor density and contractile response to both carbachol and field stimulation [Levin et al, 1988a;Kitada et al, 1989]. The current study reports on densities of muscarinic receptor subtypes in these models to determine whether these previously reported changes in bladder contractile response to muscarinic agonists are due to selective changes in one of the muscarinic receptor subtypes found in the bladder.…”