Reiser G, Heumann R, Kemper W, Lautenschlager E, Hamprecht B
Brain Res. 1977 Jul 22;130(3):495-504. doi: 10.1016/0006-8993(77)90111-1.
Electrical excitability is one of the various neuronal properties of neuroblastoma X glioma hybrid cells. At a Ca2+ concentration of 1.8 mM the action potential is inhibited by tetrodotoxin, suggesting that the inward current is carried by Na+ ions. In contrast, at a Ca2+ concentration of 20-36 mM and even in the absence of Na+, spikes (sometimes repetitive) with strong hyperpolarizing afterpotential occur, which are no longer affected by tetrodotoxin. They are, however, blocked by antagonists of Ca2+ like La3+, Co2+, Mn2+, and the synthetic compounds D-600 and BAY a-1040. This seems to indicate that at high concentrations of Ca2+, the inward current of the action potential is essentially carried by Ca2+. Sr2+, but not Mg2+ can effectively substitute for Ca2+. It slows down the time course of the action potential. Ba2+ depolarizes the membrane gradually. If Ca2+ is also present, Ba2+ causes a reduced depolarization and spontaneous action potentials with no hyperpolarizing after-potential are observed.
电兴奋性是神经母细胞瘤X胶质瘤杂交细胞的多种神经元特性之一。在钙离子浓度为1.8 mM时，河豚毒素可抑制动作电位，这表明内向电流是由钠离子携带的。相反，在钙离子浓度为20 - 36 mM时，甚至在没有钠离子的情况下，会出现具有强烈超极化后电位的尖峰（有时是重复的），这些尖峰不再受河豚毒素的影响。然而，它们会被钙离子拮抗剂如镧离子、钴离子、锰离子以及合成化合物D - 600和BAY a - 1040阻断。这似乎表明，在高浓度钙离子时，动作电位的内向电流主要由钙离子携带。锶离子而非镁离子可以有效地替代钙离子。它会减缓动作电位的时间进程。钡离子会使膜逐渐去极化。如果同时存在钙离子，钡离子会导致去极化程度降低，并且观察不到具有超极化后电位的自发动作电位。
