Lorković H
J Gen Physiol. 1967 Mar;50(4):883-91. doi: 10.1085/jgp.50.4.883.
Frog toe muscles were bathed in isotonic, sodium-free Tris chloride, methanesulfonate, or sulfate solutions containing sucrose or mannitol and varying in ionic strength from 0.006 to 0.291. By decreasing the ionic strength the curve relating the peak tension of the K contractures to the log [K] was reversibly shifted to lower [K]. Increasing the [Ca] from 1 to 4 mM almost abolished this effect. The resting uptake of (45)Ca was increased more than two times by decreasing the ionic strength from 0.125 to 0.039. It was not increased significantly by raising [Ca] from 1 to 4 mM at low or normal ionic strength. The additional uptake of (45)Ca during contractures provoked by 120 mM K was not significantly different at the two levels of ionic strength. The rate of emergence of (45)Ca from muscles loaded with (45)Ca at reduced ionic strength, was decreased. The effects of low ionic strength are discussed in terms of changes in the potential difference across a membrane with fixed negative charges on the outer surface.
将蛙趾肌肉置于等渗、无钠的 Tris 氯化物、甲磺酸盐或硫酸盐溶液中，这些溶液含有蔗糖或甘露醇，离子强度在 0.006 至 0.291 之间变化。通过降低离子强度，与 K 挛缩的峰值张力相关的曲线与 log[K]的关系可逆地向较低的[K]值移动。将[Ca]从 1 mM 增加到 4 mM 几乎消除了这种效应。通过将离子强度从 0.125 降低到 0.039，(45)Ca 的静息摄取增加了两倍多。在低离子强度或正常离子强度下，将[Ca]从 1 mM 提高到 4 mM 时，(45)Ca 的摄取没有显著增加。在两种离子强度水平下，由 120 mM K 引发的挛缩过程中(45)Ca 的额外摄取没有显著差异。在降低的离子强度下，从负载(45)Ca 的肌肉中(45)Ca 的释放速率降低。根据外表面带有固定负电荷的膜上电位差的变化讨论了低离子强度的影响。
