Kuriyama H, Oshima K, Sakamoto Y
J Physiol. 1971 Aug;217(1):179-99. doi: 10.1113/jphysiol.1971.sp009565.
The membrane properties of the longitudinal smooth muscle of the guinea-pig portal vein were investigated under various experimental conditions.1. In isotonic Krebs solution, the membrane potential (-48.7 mV), the maximum rates of rise and fall of the spike (4.6 and 2.3 V/sec respectively), the space constant (0.61 mm), the conduction velocity of excitation (0.97 cm/sec) and the time constant of the foot of the propagated spike (18.4 msec) were measured.2. The various parameters of the muscle membrane in the isotonic solution were compared with those in the hypertonic solution prepared by the addition of solid sucrose (twice the normal tonicity).3. When the muscles were perfused with hypertonic solution, marked depolarization of the membrane and increased membrane resistance occurred. These were probably due to reduction of the K permeability, increased internal resistance of the muscle and shrinkage of the muscle fibre.4. The membrane potential in isotonic and hypertonic solutions was analysed into two components, i.e. the metabolic (electrogenic Na-pump) and the ionic (electrical diffusion potential) component in the various environmental conditions.(a) In isotonic and hypertonic solutions, the membrane was depolarized by lowering the temperature or by removal of K ion from the solutions. When the tissues were rewarmed or on readdition of K ion, the membrane was markedly hyperpolarized. These hyperpolarizations of the membrane were suppressed by treatment with ouabain (10(-5) g/ml.), by warming to only 20 degrees C and by K-free solution.(b) The relationships between the membrane potential and the K in isotonic Krebs, in the hypertonic (sucrose) Krebs, in the Na-free (Tris) Krebs and in the Cl-deficient (C(6)H(5)SO(3)) Krebs were observed. The maximum slopes of the membrane depolarization against tenfold changes of K were much lower than that expected if it behaved like a K electrode.(c) In Na-free (Tris) solution, the membrane was not depolarized in isotonic condition but it was depolarized in hypertonic condition.5. The low membrane potential in hypertonic solution (-37 mV) compared with isotonic solution (-49 mV) was thought to be mainly due to suppression of K permeability of the membrane and not due to suppression of the metabolic component. The electrogenic Na-pump and the membrane potential of the portal vein was discussed in relation to other excitable cell membranes.
在各种实验条件下，对豚鼠门静脉纵行平滑肌的膜特性进行了研究。
在等渗Krebs溶液中，测量了膜电位（-48.7mV）、锋电位的最大上升和下降速率（分别为4.6和2.3V/秒）、空间常数（0.61mm）、兴奋传导速度（0.97cm/秒）以及传播锋电位足部的时间常数（18.4毫秒）。
将等渗溶液中肌肉膜的各种参数与通过添加固体蔗糖（正常张力的两倍）制备的高渗溶液中的参数进行了比较。
当用高渗溶液灌注肌肉时，膜发生明显去极化且膜电阻增加。这些可能是由于钾通透性降低、肌肉内阻增加和肌纤维收缩所致。
在各种环境条件下，将等渗和高渗溶液中的膜电位分析为两个成分，即代谢（生电钠泵）成分和离子（电扩散电位）成分。
(a) 在等渗和高渗溶液中，通过降低温度或从溶液中去除钾离子使膜去极化。当组织复温或重新添加钾离子时，膜明显超极化。膜的这些超极化被哇巴因（10⁻⁵g/ml）处理、仅升温至20℃和无钾溶液抑制。
(b) 观察了等渗Krebs、高渗（蔗糖）Krebs、无钠（Tris）Krebs和缺氯（苯磺酸）Krebs中膜电位与[K]ₒ之间的关系。膜去极化相对于[K]ₒ十倍变化的最大斜率远低于其表现得像钾电极时预期的斜率。
(c) 在无钠（Tris）溶液中，膜在等渗条件下未去极化，但在高渗条件下去极化。
