镁和辛基胍对线粒体单价阳离子转运的抑制作用

Magnesium and octylguanidinium inhibition of monovalent cation translocation in mitochondria.

作者信息

Beaty G, Gutiérrez C, López-Vancell R, Estrada S

出版信息

Acta Physiol Pharmacol Latinoam. 1986;36(3):217-32.

Abstract

We have studied the inhibitory effects of several cations (OG+, Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, La3+) on the uniport and exchange pathways for Na+ and K+ of rat liver mitochondria. Swelling of mitochondria suspended in sodium or potassium acetates indicates that: 1. Sodium passive influx to inhibited mitochondria is not affected by OG+ (in the microM range), and mM concentrations of polyvalent cations only induce a poor inhibition, the sequence being: La3+ greater than Mn2+ greater than Ca2+ greater than Mg2+ greater than Sr2+ = 0. 2. Sodium active influx is 50% inhibited by 60 microM Mg2+ or 90 microM OG+. La3+, Mn2+, Ca2+ and Sr2+ also inhibit Na+ influx (mM range). 10 mM Mg2+ or 35 microM OG+ are required to inhibit 50% K+ active influx. 3. Alkali cation efflux from partially swollen inhibited mitochondria is 50% blocked by 2 mM Mg2+ or 105 microM OG+ when sodium is the major permeable cation in the bathing solution. 3 mM Mg2+ or 3.8 microM OG+ are required for 50% inhibition when mitochondria are suspended in potassium acetate. 4. Alkali cation efflux from partially swollen respiring mitochondria suspended in sodium acetate is promoted by concentrations above 0.1-0.2 mM Mg2+ or 50-100 microM OG+. These data fit a mechanism including an energy-dependent Mg2+ and OG+ sensitive inward sodium translocator and a Mg2+ and OG+ insensitive cation/H+ exchanger working in dynamic balance.

摘要

我们研究了几种阳离子（OG⁺、Mg²⁺、Ca²⁺、Sr²⁺、Ba²⁺、Mn²⁺、La³⁺）对大鼠肝线粒体中Na⁺和K⁺的单向运输及交换途径的抑制作用。悬浮于醋酸钠或醋酸钾中的线粒体肿胀表明：1. 钠被动流入受抑制的线粒体不受微摩尔范围内的OG⁺影响，而毫摩尔浓度的多价阳离子仅产生较弱抑制，顺序为：La³⁺＞Mn²⁺＞Ca²⁺＞Mg²⁺＞Sr²⁺ = 0。2. 钠主动流入被60微摩尔的Mg²⁺或90微摩尔的OG⁺抑制50%。La³⁺、Mn²⁺、Ca²⁺和Sr²⁺也抑制钠流入（毫摩尔范围）。抑制50%的钾主动流入需要10毫摩尔的Mg²⁺或35微摩尔的OG⁺。3. 当钠是浴液中主要的可渗透阳离子时，部分肿胀受抑制的线粒体中碱金属阳离子外流被2毫摩尔的Mg²⁺或105微摩尔的OG⁺阻断50%。当线粒体悬浮于醋酸钾中时，50%抑制需要3毫摩尔的Mg²⁺或3.8微摩尔的OG⁺。4. 悬浮于醋酸钠中的部分肿胀的呼吸态线粒体中，高于0.1 - 0.2毫摩尔的Mg²⁺或50 - 100微摩尔的OG⁺浓度可促进碱金属阳离子外流。这些数据符合一种机制，该机制包括一个能量依赖的、对Mg²⁺和OG⁺敏感的内向钠转运体以及一个对Mg²⁺和OG⁺不敏感的阳离子/H⁺交换体，它们处于动态平衡。