[The membrane potential as the factor controlling the spontaneous activity of the ureter].

The spontaneous activity of various zones of the guinea pig ureter was studied by means of "sucrose gap" technique. Two of these zones, perirenal and pericystic ones are pacemakers. An increase in the K+ ions amount in the medium, electric stimulation and administration of acetylcholine, histamine or noradrenaline induced rhythmic spikes in initially inactive middle regions of the ureter. At the same time, they reduced or blocked the activity of the pacemaker zones. The existence of the MP gradient along the ureter from the ends to its central regions, is discussed.