Anderson P A, Schwab W E
J Neurophysiol. 1983 Sep;50(3):671-83. doi: 10.1152/jn.1983.50.3.671.
Neurons of the motor nerve net of the jellyfish Cyanea were impaled with microelectrodes for intracellular recordings. The cells have conventional, negative resting potentials and produce variable-amplitude action potentials with complex waveforms. The variability and complexity of these spikes is due to the superimposition of two classes of Ca2+-dependent potentials on an otherwise fast, clean action potential. Repetitive stimulation and ionic manipulation reveal that most superimposed potentials are chemically induced excitatory postsynaptic potentials (EPSPs). These account for the complexity and variability of the action potential. The remaining potential is interpreted as a Ca2+ component of the action potential. The action potential is a Na+-dependent but tetrodotoxin- (TTX) insensitive event. Repolarization is achieved by two pharmacologically distinct mechanisms: a tetraethylammonium- (TEA) and 4-amino-pyridine- (4-AP) sensitive K+ efflux and a delayed, Ca2+-activated, K+ efflux. The latter is responsible for the afterhyperpolarization that follows the action potential. The results indicated that these neurons are physiologically conventional. This is interesting in view of the phylogenetic primitiveness of the preparation and important, since it means that this preparation can provide generally useful information on chemical synaptic physiology.
用微电极刺入海蜇（霞水母属）运动神经网的神经元进行细胞内记录。这些细胞具有传统的负静息电位，并产生波形复杂、幅度可变的动作电位。这些峰电位的变异性和复杂性是由于在原本快速、清晰的动作电位上叠加了两类钙依赖性电位。重复刺激和离子操作表明，大多数叠加电位是化学诱导的兴奋性突触后电位（EPSP）。这些解释了动作电位的复杂性和变异性。其余的电位被解释为动作电位的钙成分。动作电位是一种依赖钠离子但对河豚毒素（TTX）不敏感的事件。复极化通过两种药理学上不同的机制实现：一种对四乙铵（TEA）和4-氨基吡啶（4-AP）敏感的钾离子外流，以及一种延迟的、钙激活的钾离子外流。后者负责动作电位后的超极化后电位。结果表明，这些神经元在生理上是传统的。鉴于该标本在系统发育上的原始性，这一点很有趣，而且很重要，因为这意味着该标本可以提供关于化学突触生理学的普遍有用的信息。
