Chiarandini D J, Stefani E
J Gen Physiol. 1967 May;50(5):1183-200. doi: 10.1085/jgp.50.5.1183.
The ionic bases of the "positive" afterpotential (ap) have been examined in the so-called DInhi neurons of the central nervous system of Cryptomphallus aspersa. In these cells E(K) has been determined and its value compared with the equilibrium, potential of the ap (E(ap)). It has been found that in half of the studied cells the E(K) value is very close to E(ap) whereas in another half, the difference (E(K) - E(ap)) is large and amounts to circa -10 mv. The effects of changes in the concentration gradients of K(+), Cl(-), and Na(+) were assayed in both groups of cells. When the [K(i)/K ratio is reduced in both groups of neurons, the ap amplitude and the E(ap) diminished. In cells displaying a large (E(K) - E(ap)), Cl-free Ringer's solution diminished the ap amplitude and E(ap), but produced no effect in the neurons with a reduced (E(K) - E(ap)). A similar effect was observed if [Cl], was increased by intracellular injection of NaCl. Changes in both Na and Na were ineffective. It is concluded that K(+) is the only ion involved in the origin of the ap in the groups of cells with a low value for (E(K) - E(ap)). On the contrary, the ap of the neurons presenting large (E(K) - E(ap)) is produced by a simultaneous increase in the fluxes of both K(+) and Cl(-).
在散大隐孔菌中枢神经系统所谓的DInhi神经元中，研究了“正”后电位（ap）的离子基础。在这些细胞中测定了E(K)，并将其值与ap的平衡电位（E(ap)）进行比较。结果发现，在一半的研究细胞中，E(K)值非常接近E(ap)，而在另一半细胞中，差异（E(K) - E(ap)）很大，约为-10 mV。在两组细胞中都检测了K(+)、Cl(-)和Na(+)浓度梯度变化的影响。当两组神经元中[K(i)/K比值降低时，ap幅度和E(ap)减小。在显示大的（E(K) - E(ap)）的细胞中，无Cl的林格氏液降低了ap幅度和E(ap)，但对（E(K) - E(ap)）降低的神经元没有影响。如果通过细胞内注射NaCl增加[Cl]，也会观察到类似的效果。Na和Na的变化均无效。得出的结论是，在（E(K) - E(ap)）值较低的细胞组中，K(+)是参与ap产生的唯一离子。相反，呈现大的（E(K) - E(ap)）的神经元的ap是由K(+)和Cl(-)通量同时增加产生的。
