The role of ureteral peristaltic rate and bolus volume on increasing urine flow.

Electromyogram (EMG) and bolus volume of ureteral peristalsis were measured during gradual and rapid urinary flow increase in mongrel dogs. In acute diuresis induced by furosemide, the ureteral peristaltic rate rose and then the bolus volume increased with a consequent increase of urine flow. During a course of gradually increasing urine secretion, the ureter showed varying responses in respect to peristaltic rate (i.e., increase, no change and decrease) but changes in the bolus volume consistently made up for the rate alterations, thereby eventually maintaining an efficient equilibrium of these two urodynamic parameters to effect an increase in urine flow. The ureteral peristaltic rate increases only several times in polyuria as compared to the rate in oliguria, whereas the bolus volume of urine increases by a factor of 100. This indicates that it is not so much the ureteral peristaltic rate as the bolus volume which plays a principal part in the transport of urine through the ureter.