[The mechanisms of the formation of the plateau phase of the ureteral action potential].

The duration of the AP plateau was shown to be controlled by the Na+ and Li+ ions in the solution incubating the smooth muscle of the ureter. Addition of ouabain to the sodium solution or replacement of the Na+ ions by the Li+ those shorted the plateau duration. The generation of the AP plateau seems to be due to participation of the Na(+)-Ca++ exchange mechanism.