Kuriyama H, Tomita T
J Gen Physiol. 1970 Feb;55(2):147-62. doi: 10.1085/jgp.55.2.147.
The configuration of the electrotonic potential and the action potential observed by the double sucrose-gap method was similar to that observed with a microelectrode inserted into a cell in the center pool between the gaps. In the taenia and the ureter, the evoked spike was larger in low Na or in Na-free (sucrose substitute) solution than in normal solution. However, the plateau component in the ureter was suppressed in the absence of Na. In Ca-free solution containing Mg (3-5 mM) and Na (137 mM), the membrane potential and membrane resistance were normal, but no spike could be elicited in both the taenia and ureter. Replacement of Ca with Sr did not affect the spike in the taenia, nor the spike component of the ureter but prolonged the plateau component. The prolonged plateau disappeared on removal of Na, while repetitive spikes could still be evoked. It was concluded that the spike activity in the taenia and in the ureter of the guinea pig is due to Ca entry, that the plateau component in the ureter is due to an increase in the Na conductance of the membrane, and that both mechanisms, for the spike and for the plateau, are separately controlled by Ca bound in the membrane.
用双蔗糖间隙法观察到的电紧张电位和动作电位的形态，与用微电极插入间隙之间中央池中的细胞所观察到的相似。在绦虫和输尿管中，诱发的锋电位在低钠或无钠（蔗糖替代）溶液中比在正常溶液中更大。然而，在无钠的情况下，输尿管中的平台成分受到抑制。在含有镁（3 - 5 mM）和钠（137 mM）的无钙溶液中，膜电位和膜电阻正常，但绦虫和输尿管中均不能诱发锋电位。用锶替代钙不影响绦虫中的锋电位，也不影响输尿管中的锋电位成分，但延长了平台成分。去除钠后，延长的平台消失，而仍可诱发重复锋电位。得出的结论是，豚鼠绦虫和输尿管中的锋电位活动是由于钙内流，输尿管中的平台成分是由于膜钠电导增加，并且锋电位和平台的这两种机制分别受膜中结合的钙控制。
