Pacemaker system in the control of ureteral peristaltic rate in the multicalyceal kidney of the pig.

Temporal and distributive properties of ureteral peristaltic contractions in the anesthetized pig have been examined. Interperistaltic time intervals have been recorded, and their frequency during different urine flow rates has been compared. The results show that ureteral peristalsis is increased at high urine flow rates to a maximum of approximately 0.06 Hz. It is further shown from the interperistaltic histograms that ureteral contractions are not clustered into a discreet multimodal spectrum. This represents the first evidence that the multicalyceal kidney has a system of pacemakers of differing fundamental frequencies, tending toward synchronism as urine flow increases.