Control of ureteral peristalsis during changes in intravesical pressure

Studies of the ureteral response to changes in intravesical pressure (IP) have been conducted by surgically altering the neural and hydrodynamic integrity of canine ureters. Ureteral function was assessed by acute and chronic recordings of ongoing electrical activity. Intact control ureters responded (acute to 56 per cent; chronic to 83 per cent) to elevated IP with immediate increases and to decreases in IP with slowing or cessation of activity. Acute ureteral ligation mimicked the effects of increased IP, except the responses were much slower. Ureterotomy and the resultant extravasation of urine did not alter the ureteral response. Disruption of renal nerves, whether by selective sectioning or by nephrectomy, was associated with exaggerated ureteral frequency responses which were delayed in onset. Ureters lacking neural connections with the bladder responded with bursts of multiple spikes and increases in the force of peristalsis. These observations are discussed in terms of the myogenic and neurogenic control of ureteral peristalsis.