Videomicroscopic imaging of ureteral peristaltic function in rats during cystometry

Videomicroscopic imaging of the upper urinary tract was performed in 26 female anesthetized rats during bladder filling and micturition. Recordings were made of the pressure of the renal pelvis through a nephrostomy and visualization of the dynamics of the ureteral bolus. Peristaltic velocity, frequency, bolus length, and direction urine bolus propagation were derived on the basis of image processing using indigo carmine for contrast. In addition, nonstop cystometrograms were performed at an infusion rate of 0.22 ml/min characterizing bladder filling and micturition reflexes. Using this setup the pharmacological response of the upper and lower urinary tract dynamics to intravenous oxybutynin and LY274614 was evaluated and compared to observations made with placebo time controls. The data, obtained from the time controls, indicate that there is a significant time-dependent influence on the upper urinary function caused by the experimental methodology in the frequency of ureteral peristalsis and length of the bolus. Oxybutynin produced a significant increase in the length of the but not in the velocity of the bolus. LY274614 depressed pelvic pressure and ureteral frequency and increased bolus length. It is concluded that videomicroscopic imaging, in association with nonstop cystometry, provides a unique method to investigate the pharmacological effects of centrally and peripherally acting drugs on the upper and lower urinary tract function without mechanical manipulation of the ureter.