Kaplán P, Matejovicová M, Mézesová V
Department of Biochemistry, Jessenius Medical Faculty, Comenius University, Martin, Slovak Republic.
Neurochem Res. 1997 Dec;22(12):1523-9. doi: 10.1023/a:1021918931780.
The effect of oxidative stress, induced by Fe(2+)-EDTA system, on Na+,K(+)-ATPase, Na+/CA2+ exchanger and membrane fluidity of synaptosomes was investigated. Synaptosomes isolated from gerbil whole forebrain were incubated in the presence of 200 microM FeSO4-EDTA per mg of protein at 37 degrees C for 30 min. The oxidative insult reduced Na+,K(+)-ATPase activity by 50.7 +/- 5.0% and Na+/Ca2+ exchanger activity measured in potassium and choline media by 47.1 +/- 7.2% and 46.7 +/- 8.6%, respectively. Membrane fluidity was also significantly reduced as observed with the 1,6-diphenyl-1,3,5-hexatriene probe. Stobadine, a pyridoindole derivative, prevented the decrease in membrane fluidity and in Na+/Ca2+ exchanger activity. The Na+,K(+)-ATPase activity was only partially protected by this lipid antioxidant, indicating a more complex mechanism of inhibition of this protein. The results of the present study suggest that the Na+/Ca2+ exchanger and the Na+,K(+)-ATPase are involved in oxidation stress-mediated disturbances of intracellular ion homeostasis and may contribute to cell injury.
研究了由Fe(2+)-EDTA系统诱导的氧化应激对突触体的Na+,K(+)-ATP酶、Na+/Ca2+交换体及膜流动性的影响。从沙鼠全前脑分离的突触体在每毫克蛋白质含有200微摩尔FeSO4-EDTA的条件下，于37℃孵育30分钟。氧化损伤使Na+,K(+)-ATP酶活性降低了50.7±5.0%，在钾和胆碱介质中测得的Na+/Ca2+交换体活性分别降低了47.1±7.2%和46.7±8.6%。用1,6-二苯基-1,3,5-己三烯探针观察到膜流动性也显著降低。吡啶吲哚衍生物司他定可防止膜流动性和Na+/Ca2+交换体活性的降低。这种脂质抗氧化剂仅部分保护了Na+,K(+)-ATP酶活性，表明对该蛋白质的抑制机制更为复杂。本研究结果提示，Na+/Ca2+交换体和Na+,K(+)-ATP酶参与了氧化应激介导的细胞内离子稳态紊乱，可能导致细胞损伤。
