Khodorov B, Pinelis V, Vergun O, Storozhevykh T, Vinskaya N
Institute of General Pathology and Pathophysiology, Moscow, Russian Federation.
FEBS Lett. 1996 Nov 18;397(2-3):230-4. doi: 10.1016/s0014-5793(96)01139-8.
The purpose of our work was to study the relationship between glutamate (GLU)-induced mitochondrial depolarization and deterioration of neuronal Ca2+ homeostasis following a prolonged GLU challenge. The experiments were performed on cultured rat cerebellar granule cells using the fluorescent probes, rhodamine 123 and fura-2. All the cells, in which 100 microM GLU (10 microM glycine, 0 Mg2+) induced only relatively slight mitochondrial depolarization (1.1-1.3-fold increase in rhodamine 123 fluorescence), retained their ability to recover [Ca2+]i following a prolonged GLU challenge. In contrast, the cells in which GLU treatment induced pronounced mitochondrial depolarization (2-4-fold increase in rhodamine 123 fluorescence), exhibited a high Ca2+ plateau in the post-glutamate period. Application of 3-5 mM NaCN or 0.25-1 microM FCCP during this Ca2+ plateau phase usually failed to produce a further noticeable increase in [Ca2+]i. Regression analysis revealed a good correlation (r2 = 0.88 +/- 0.03, n = 19) between the increase in the percentage of rhodamine 123 fluorescence and the post-glutamate [Ca2+]i. Collectively, the results obtained led us to conclude that the GLU-induced neuronal Ca2+ overload was due to the collapse of the mitochondrial potential and subsequent ATP depletion.
我们这项工作的目的是研究谷氨酸（GLU）诱导的线粒体去极化与长时间GLU刺激后神经元钙稳态恶化之间的关系。实验使用罗丹明123和fura-2荧光探针在培养的大鼠小脑颗粒细胞上进行。所有细胞，在100微摩尔GLU（10微摩尔甘氨酸，0毫摩尔镁离子）仅诱导相对轻微的线粒体去极化（罗丹明123荧光增加1.1 - 1.3倍）的情况下，在长时间GLU刺激后仍保留恢复细胞内钙浓度（[Ca2+]i）的能力。相比之下，GLU处理诱导明显线粒体去极化（罗丹明123荧光增加2 - 4倍）的细胞，在谷氨酸作用后的时期表现出高钙平台期。在此钙平台期应用3 - 5毫摩尔氰化钠或0.25 - 1微摩尔羰基氰化物4-(三氟甲氧基)苯腙（FCCP）通常不会使[Ca2+]i进一步显著增加。回归分析显示罗丹明123荧光百分比增加与谷氨酸作用后的[Ca2+]i之间具有良好的相关性（r2 = 0.88 ± 0.03，n = 19）。总体而言，所获得的结果使我们得出结论，GLU诱导的神经元钙超载是由于线粒体电位的崩溃以及随后的ATP耗竭。
