The relationship of extrinsic nerves to motor activity of the upper urinary tract. In vivo studies on the pig.

Ureteral activity in the anesthetized pig was monitored by indwelling open-ended nonocclusive fluid-filled catheters. After a preliminary control period, electrical stimulation was applied to the renal/ureteral nerves, anterior and posterior vagi, and the preaortic abdominal nerve plexuses. Such stimulation was uniformly without effect upon renal pelvis and ureteral activity as observed visually and also as recorded by the intraluminal catheters. Excessive mechanical stimulation of the ureter and collecting system on one side did not induce any change whatsoever in the motor activity of the contralateral system, i.e., no "reflex" activity was demonstrable between the two sides. After ensuring complete devascularization of one kidney (and hence halting urine production by the kidney) regularly spaced anterograde contraction complexes were recorded from the homolateral ureter for periods in excess of 40 min. This latter phenomenon is discussed in relation to the concept of an upper urinary tract pacemaker.