Renal pelvic peristalsis in pigs during standardized flow rate variations.

In the multicalyceal kidney of the pig renal pelvic pressure waves were investigated in 15 units. The pelvis was perfused with bodywarm saline gradually increased from 0-20 ml/min. The study showed a predominantly unimodal activity but all systems showed periods of instability which were characterized by coupled pressure waves, high frequencies and cascade emptying. The amplitude of the pressure waves increased with increasing flow and the study showed correlation between low amplitude and high frequency and vice versa.