Effects of Artificial Obstruction on the Function of the Upper Urinary Tract of Guinea Pigs, Rats and Pigs

Abstract

Surgical interruption of the ureteral continuity and re-anastomosis cause a temporary disruption of the peristaltic wave at the anastomosis site. Ureteral peristalsis is restored by ureteral contractions associated with retroperistalsis as well as a decreased contraction frequency. Uretero-ureteral anastomosis in rats, pyelo-ureteral anastomosis in guinea pigs and pyeloplasty in pigs seem to influence the upper urinary tract similarly to a chronical functional obstruction, causing changes in pyelo-ureteral motility and spontaneous muscular activity of the renal pelvic and ureteral wall as well as biomechanical and histological characteristics.

Interstitial cell of Cajal-like cells in the upper urinary tract

“…The relative presence of these 2 populations of pacemaker cells determines the decreasing frequency of contraction with distance from the renal fornix. In the absence of the proximal pacemaker drive from atypical SMC after pyeloureteral/ureteral obstruction or surgery, ICC-like cell pacemaking provides a compensatory mechanism allowing the ureter to maintain rudimentary peristaltic waves and movement of urine from the pyelon to the bladder [67]. In contrast the increased contractility of the renal pelvis proximal of any pyeloureteric injury may well arise from the reduced numbers of integrating ICC-like cells.…”

“…Spontaneous low frequency peristaltic waves occur in the distal ureter in human and many mammals after ureteric surgery, anastomosis or partial/ chronic UPJ obstruction [67]; conditions which would disconnect the distal regions of the UUT form the proximal atypical SMC drive. Proximal to the site of pyeloureteric injury the renal pelvis enlarges often irreversibly arising from a thickening of the wall associated with a loss of ICC-like cell number and intrinsic motor/ sensory innervation, an accumulation of interstitial collagen and elastin and an increase/ decrease in the spontaneous contractile activity [58,[67][68][69][70][71]. The mechanisms underlying and the functional consequences of this remodelling of the UUT remains little understood and is now becoming an area of some interest in the literature.…”

Demonstration of intrinsic innervation of the guinea pig upper urinary tract using whole‐mount preparation

“…For standard AChE histochemistry, parts of specimens were incubated in the two stock solutions at 37 C following the method of Karnowsky and Roots. 19 The specimens were incubated with the freshly prepared staining solution (10 ml of acetylthiocholine-jodid 300 mg/60 ml Aqua d.; tri-sodium (hydrogen)citrate 1.5 hydr.…”

Goat ureter-an alternative model for measuring ureteral peristalsis

“…The tissue was placed in an organ bath (MM 221, Inco Instruments, Ambala, India) containing warm MR solution. The distal end of the ureter was mounted over (Liu, 1962) Sheep ureter (Angelo-Khattar et al, 1989) Pig ureter Human ureter (Iselin et al, 1998) Guinea pig ureter/ Rat ureter (Tilling et al, 2004) Rabbit ureter (Wu et al, 2002) Chicken ureter (Hammer et al, 1993) the J tube connected to a modified reservoir (of length 15 cm, diameter 1cm and capacity 10 ml, as it has been observed that the conventional reservoir suggested in the Trendelenberg method causes early fatigue of the tissue; Figs. 7 and 8).…”