EFFECTS OF REPETITIVE STIMULI AND TEMPERATURERATURE ON URETER ACTION POTENTIALS

Abstract

The effects of repetitive stimuli and temperature variation on the rate of rise and duration of action potentials, of the ureter smooth muscle of cat and guinea pig, were studied with the aid of intracellular potential recording techniques. The recovery process of action potentials in the ureter muscle of cat was examined. During the early relative refractory period, slow and small potential changes were recorded. In the later phase, an action potential of slow rising character and decreased height was recorded. In guinea pig ureter, the action potential which was observed in the relative refractory period showed a slow rising rate, reduced oscillatory potentials and shortened duration. The rapid falling phase of the repolarization could be superimposable when the ureter muscle was repetitively stimulated. This finding resembled that found in vertebrate myocardium. The rate of rise of potential, the duration of action potentials and the conduction velocity were decreased when the temperature of the bathing fluid was lowered,.