Parallel recording of renal pelvic pressure, ureteral electromyogram and urine volume was carried out in dogs given intravenous injections of noradrenaline, isoproterenol or acetylcholine. With noradrenaline, an increase in urine volume was observed coincidentally with an elevation of renal pelvic pressure and an increase in frequency of ureteral peristalsis. In response to isoproterenol, the urine volume diminished in harmony with flattening of pelvic pressure waves and the disappearance of ureteral peristalsis. Conversely, ureteral peristalsis increased in frequency immediately after the administration of acetylcholine, while the urine volume diminished.