Vyskocil F
Brain Res. 1977 Sep 16;133(2):315-28. doi: 10.1016/0006-8993(77)90767-3.
Diazepam inconcentrations of 10(-6) and 10(-5) M effectively blocks trains of action potentials (AP) in individual rat diaphragm muscle fibres 'in vitro'. Single APs, evoked and recorded intracellularly with double microelectrodes, were not affected by diazepam. Trains of APs, evoked in diaphragm fibers in a SO42-- -medium (Cl-- -free), were not affected by diazepam. Diazepam decreased the dependence of the membrane resting potential of muscle cells in chloride media on elevated external potassium whereas no effect was observed in SO42-- --Cl-- -free saline. Similar to in the rat diaphragm, diazepam blocked the trains of AP of individual muscle fibres in the frog sartorius muscle (Cl-- -medium). Diazepam did not affect the spontaneous fibrillatory APs recorded extracellularly from rat gastrocnemius muscles 10 days after denervation. Diazepam apparently increases the resting permeability of the muscle fibre memebrane for chloride ions. In the presence of the drug, the higher permeability for Cl- diminishes the depolarization caused by the potassium released and accumulated in the vicinity of the membrane in the course of AP. The muscle fibre membrane thus does not respond by repetitive activity when partially depolarized and only one AP can be evoked when diazepam is present. It is suggested that similar changes in Cl-- permeability may occur in brain excitable structures after diazepam administration and may account for some of the therapeutic effects of the drug.
10⁻⁶ 和 10⁻⁵ M 浓度的地西泮可有效阻断体外培养的单个大鼠膈肌纤维中的动作电位（AP）序列。用双微电极细胞内诱发和记录的单个动作电位不受地西泮影响。在SO₄²⁻ 培养基（无Cl⁻）中诱发的膈肌纤维动作电位序列也不受地西泮影响。地西泮降低了氯化物培养基中肌肉细胞膜静息电位对细胞外高钾的依赖性，而在无SO₄²⁻ 和Cl⁻ 的盐溶液中未观察到这种影响。与大鼠膈肌情况相似，地西泮可阻断青蛙缝匠肌（Cl⁻ 培养基）中单个肌肉纤维的动作电位序列。地西泮不影响去神经支配10天后从大鼠腓肠肌细胞外记录到的自发纤颤动作电位。地西泮明显增加了肌肉纤维膜对氯离子的静息通透性。在药物存在的情况下，对Cl⁻ 的较高通透性减少了动作电位过程中在膜附近释放和积累的钾离子引起的去极化。因此，当部分去极化时，肌肉纤维膜不会产生重复活动，并且当存在地西泮时只能诱发一个动作电位。有人提出，给药后在脑可兴奋结构中可能会发生类似的Cl⁻ 通透性变化，这可能是该药物某些治疗作用的原因。
