抄録
The effect of tetraethylammonium (TEA) on the electrical activity of mouse myometrium was investigated in combination with the use of Mn and Cd.
1. With low concentration of TEA (3 mM), the overshoot of the spike potential increased by about 10mV. With high concentration (10-30 mM), the overshoot was increased more and the repolarization was prolonged. The rate of rise of the spike potential increased by 3 mM TEA, but higher concentrations did not cause further increase.
2. Membrane potential was not changed by TEA nor was the electrotonic potential in response to the hyperpolarizing current affected. In the Mn-Locke solution, where Ca was substituted with 2.2 mm Mn and spike generation was abolished, the electrotonic response to the depolarizing current became larger when TEA was applied.
3. The spike potential, which had been once abolished in the Mn-added Locke solution, reappeared by applying TEA. TEA did not restore the spike generation in Cd-treated tissue.
4. Spike potential in Locke solution with Mn and TEA-added was gradually suppressed by repetitive electric stimuli with 1 Hz. It was restored by interposing longer intervals or by raising external Ca concentration.
