Inhibitory effects of propiverine, atropine and oxybutynin on bladder instability in rats with infravesical outlet obstruction

Abstract

Objective To compare the inhibitory eCects of propiveratropine increased the RV only in normal rats (P<0.01) and oxybutynin had no significant eCect on ine HCl (BUP-4) with those of atropine and oxybutynin on the detrusor instability induced by partial obstruc-RV. Increases in compliance after the administration of each drug were significant only in obstructed rats tion of the bladder neck of female rats. Materials and methods Partial obstruction was created (P<0.01) and were markedly higher after oxybutynin (780%) than after the other drugs (180-250%). The using partial ligation of the proximal urethra in 20 female Sprague-Dawley rats. Both the obstructed rats frequencies and amplitude of SA after injection with each drug were significantly lower only in obstructed and a control group of 15 rats were evaluated cystometrically about 6 weeks later and the values comrats, but in these rats, there were no significant diCerences in this reduction after injecting oxybutynin pared both at baseline and after injection with BUP-4, atropine or oxybutynin. During cystometry, the blador BUP-4, whereas they were significantly greater after injecting oxybutynin than after atropine. der capacity (BC), residual volume (RV), compliance and frequency of spontaneous activity (SA) were Conclusion Partial bladder outlet obstruction successfully created a hyperactive (unstable) bladder, typified determined. Results The BC, RV and frequency of SA were signifiby increased BC, RV, frequency of SA and a marked decrease in compliance. The greater BC, lower MP cantly increased, and compliance markedly decreased, in obstructed compared with normal rats. The micturand frequency and amplitude of SA were prominent after the administration of BUP-4. Thus it is suggested ition pressure was significantly decreased only after injection with BUP-4 in both normal and obstructed that BUP-4 eCectively inhibited bladder instability in rats induced by infravesical outlet obstruction and rats. For both, the BC was increased significantly after injection with atropine or BUP-4 (P<0.05), with the was more eCective than oxybutynin in increasing BC.

Urodynamic effects of oxybutynin and tolterodine in conscious and anesthetized rats under different cystometrographic conditions

“…In addition, in this last experimental condition, oxybutynin did not modify the frequency and amplitude of the non-voiding contractions. These findings are in agreement with the lack of activity shown by tolterodine in the same model [31], whereas Kwak and Lee [14] reported a significant decrease of frequency and amplitude of the non voiding contractions in anesthetized rats after intraarterial administration of 1 mg/kg oxybutynin.…”

“…Outflow obstruction may be associated with changes in the cholinergic function of the bladder associated with an increase of atropine-resistance. Again, the bladder instability seen in obstructed rats seems to be particularly related to the atropine-resistant contraction component, where ATP and prostaglandins play an important role [14]. However, we found that oxybutynin did not increase BVC either in rats under infusion of the bladder with suramin, or in obstructed rats.…”

Experimental model of bladder instability in rabbits

“…We have observed that after 4 weeks of partial obstruction, bladder weigh in the animals of G2 group (obstructed) was 2.5 times higher than in G1 group (control). Other authors (13,15,17) observed a significant increase in rabbits' bladder weight after 4 weeks of partial obstruction. This fact could occur due to the presence of hypertrophy and hyperplasia of vesical wall (20).…”

“…Thus, there are different experimental models described for partial bladder outlet obstruction using guinea pig (3), rabbit (4,5), cat (6), dog (7), pig (8), and rat (9). The models described aimed to characterize bladder functional alterations caused by partial obstruction, but few works take into account the development of uninhib-ited detrusor contractions (9)(10)(11)(12)(13). This obstruction was performed in most cases constricting the urethrovesical junction with a suture tie (14,15), a polyethylene tube (16), or a silicone strip (17).…”

The Unstable Detrusor

“…It has a dual mode of action which includes both anticholinergic and calcium antagonistic properties. In rats with detrusor instability induced artificially by outflow obstruction, this agent appears to be as effective as oxybutynin at suppressing spontaneous detrusor activity [38]. Direct comparative trials in humans with oxybutynin and/or tolterodine would be of interest.…”