[Studies on the function of the upper urinary tract. XXVI. The influence of the rise of ureteral intraluminal pressure on ureteral peristalsis during ureteral obstruction].

The present investigation was undertaken in order to examine the change in ureteral peristalsis during acute complete occlusion of the ureter. Unilateral ureteral obstruction was produced in 13 mongrel dogs. Parameters consisting of the ureteral intraluminal pressure, ureteral electromyogram (EMG), urine volume, specific gravity of urine, and blood pressure were measured simultaneously during occlusion. The results obtained were as follows: 1) Under the condition of complete occlusion, the resting ureteral pressure inducing the shortest discharge interval (less than 4 seconds) was in the range of 15-20 cmH2O. 2) When the resting pressure increased over 25 cmH2O, the effective contractile pressure due to ureteral peristalsis disappeared in 7 ureters despite their EMGs were persistent. In cases where the contractile pressure was maintained, it tended to decrease gradually. 3) The conduction velocity of peristalsis did not change significantly in both cases. 4) No significant changes were seen in the urine volume, specific gravity of urine, and blood pressure. On the other hand, slight retrograde peristalsis was observed in 8 dogs under the condition of obstruction.