Changes in the ureteral peristaltic rate and the bolus volume in gradual and rapid urinary flow increase.

The electromyogram and bolus volume of ureteral peristalsis were measured during gradual and rapid urinary flow increase, using 16 mongrel dogs. When the urine flow was increased rapidly by administration of diuretics, the ureteral peristaltic rate always increased first, then the urine bolus volume increased and finally the ureter became a urinary column without forming the urine bolus. When the urine flow was increased gradually by intravenous drip infusion of saline solution, the ureteral peristaltic rate and urine bolus volume did not always increase in spite of urinary flow increase. The peristaltic rate and bolus volume helped each other for effective urinary transport, as both of them not only always increase but also one of them occasionally decreased.