Eugéne D, Barets A
J Physiol (Paris). 1982;78(9):814-20.
The deep lateral muscle fibres of the trout (Salmo irideus) have a polyaxonal and distributed motor innervation. Electrical activity was investigated using intracellular microelectrodes under current clamp conditions. In high-potassium solutions, the resting membrane potential depended on the external potassium concentration. However low-potassium or low-chloride solutions produced steady-state membrane depolarizations. In such solutions, a large decrease in the external sodium concentration slightly repolarized the membrane. Inward and outward rectifications could be observed. Only the outward rectification was decreased by tetraethylammonium ions (20 mM). In high-sodium solutions, the application of depolarizing currents induced an autoregenerative electrical activity which was suppressed by tetrodotoxin (10 microM). Tetraethylammonium ions (20 mM) increased both amplitude and duration of the action potential. It is concluded that the membrane of the muscle fibres has several electrical properties similar to those of twitch skeletal fibres of vertebrates. The increase in motor nerve stimulation induced both junctional potentials and spike-like responses. The latter had a variable amplitude and rarely reached the zero potential.
虹鳟鱼（Salmo irideus）的深层外侧肌纤维具有多轴突且分布广泛的运动神经支配。在电流钳制条件下，使用细胞内微电极研究其电活动。在高钾溶液中，静息膜电位取决于外部钾浓度。然而，低钾或低氯溶液会导致膜的稳态去极化。在这种溶液中，外部钠浓度的大幅降低会使膜稍微复极化。可以观察到内向整流和外向整流。只有外向整流会被四乙铵离子（20 mM）降低。在高钠溶液中，施加去极化电流会诱发一种自再生电活动，该活动被河豚毒素（10 microM）抑制。四乙铵离子（20 mM）会增加动作电位的幅度和持续时间。得出的结论是，肌纤维膜具有一些与脊椎动物的快肌纤维相似的电特性。运动神经刺激的增加会诱发接头电位和尖峰样反应。后者的幅度可变，很少达到零电位。
