Dynamics of the urinary tract during induced vesico-ureteric reflux in pigs. II.

The ureterovesical junction was bypassed on the left side with a tube in 9 pigs in order to study the dynamic alterations a vesico-ureteric reflux produces in a previously patent pyelo-ureter. Before bypassing, the median ureteric baseline activity was 1.6-2.0 A.P./min (action potentials/min). During bladder filling the median activity increased by 15-44% to 2.3 A.P./min, together with a slight increase in pelvic pressure. In the refluxing ureters the median baseline ureteric activity was 1.6 A.P./min. During bladder filling the pelvic pressure was the same as the bladder pressure and the median ureteric activity increased by 88% to 3.0 A.P./min. This increase in activity was seen as soon as the bladder filling started. The study adds information to suggest a neurogenic mediated reaction to sudden increases in bladder volume and pressure.