実験的膀胱頚部通過障害 第1報 : 膀胱内圧の変化と膀胱平滑筋のacetylcholineに対する収縮反応について

Abstract

The influence of outflow obstruction on bladder function was studied in 17 female dogs obstructed by a mild ligation of the proximal urethra for 1 week to 6 months, using a cystometric method. The bladder wall tension was calculated from the values of bladder capacity and maximum voiding pressure (MVP) by the Laplace's law. In addition, the contractility of detrusor muscle strips to acetylcholine was studied by means of an isometric in vitro technique. The cystometric changes of the 17 dogs were classified into the following 4 types; Type I showing a markedly decreased capacity and increased MVP, which was demonstrated in 7 dogs. Type II showing a slightly decreased capacity and increased MVP, which was demonstrated in 4 dogs. Type III showing an increased capacity and MVP, which was demonstrated in 2 dogs. Type IV showing an increased capacity and decreased MVP, which was demonstrated in 4 dogs. Type I was mainly manifested after the obstruction periods of 1 to 3 weeks and type II after those of 6 months. There was no special correlation between type IV and the obstruction periods. The bladder wall tension showed postoperatively no significant change in type I, significant increase in types II and III, slight decrease in type IV. As compared with 8 control dogs, the sensitivity of the experimental dogs to acetylcholine was little different in type I, slightly low in type II, significantly high in type III, and significantly low in type IV. From these results, it was suggested that functional changes of the bladder resulted from the obstruction may be introduced by a possible concern of neurogenic factors in part.