The effect of urine on ureteral motility.

Ureteral rings were used to study in vitro spontaneous phasic contractions, similar to the peristaltic waves in vivo. Addition of small amounts of sheep or human urine inhibited or totally blocked rhythmic contractions, and induced tonic contracture. Changes in osmolality induced by the addition of urine were analysed and electrolyte and protein catabolites determined. Similar changes in osmolality which were induced by the addition of urine were elected by adding sucrose to the organ bath. This had the opposite effect, it increased both the frequency and the amplitude of rhythmic contractions. Therefore, an increase in osmolality per se cannot be responsible for the observed changes of motility. A reduction of pH, resulted in similar changes of motility. In an in-vivo situation with a damaged urothelial barrier there is reason to believe that entrance of urine to the lamina propria and smooth muscle cells will induce profound changes of motility.