Marian M, Bindoli A, Callegarin F, Rigobello M P, Vincenti E, Bragadin M, Scutari G
Department of Biological Chemistry, University of Padova, Italy.
Neurochem Res. 1999 Jul;24(7):875-81. doi: 10.1023/a:1020910131237.
The effect of 2,6-diisopropylphenol (propofol) in comparison to that of the halogenated anesthetics enflurane, isoflurane, and halothane on tetrapenylphosphonium uptake by rat brain synaptosomes was studied. A direct method to separately measure the synaptosomal and the mitochondrial transmembrane potential by using the tetraphenylphosphonium cation (TPP+) was utilized. The latter is a lipophylic charged molecule which distributes between two compartments according to the transmembrane electrical potential in the presence or absence of 60 mM KCl as a synaptosomal membrane depolarizing agent. After previously reporting the damages induced by general anesthetics on isolated mitochondria, the aim of this paper was to study their possible action on the synaptosomal membrane potential and whether or not drugs concentrations damaging isolated mitochondria are also effective on synaptosomal mitochondria. The results indicated that, in the presence of glucose, mitochondria included in synaptosomes were able to maintain a transmembrane potential of 202+/-8 mV (mean +/- SD) while the synaptosomal membrane showed a potential of 78+/-8 mV (mean +/- SD). When anesthetic concentrations (0.6-1 mM propofol, 10-40 microM enflurane, 30-50 microM isoflurane, 8-15 microM halothane) that impair mitochondrial energy metabolism were used, the synaptosomal transmembrane potential was maintained and, in addition, a slight increase of the TPP+ taken up was observed as the anesthetic concentration was increased.
研究了2,6 - 二异丙基苯酚（丙泊酚）与卤化麻醉剂恩氟烷、异氟烷和氟烷相比，对大鼠脑突触体摄取四苯基鏻的影响。采用了一种直接方法，即使用四苯基鏻阳离子（TPP +）分别测量突触体和线粒体的跨膜电位。后者是一种亲脂性带电分子，在存在或不存在60 mM KCl作为突触体膜去极化剂的情况下，根据跨膜电势分布在两个区室之间。在先前报道了全身麻醉剂对分离线粒体的损伤后，本文的目的是研究它们对突触体膜电位的可能作用，以及损害分离线粒体的药物浓度对突触体线粒体是否也有效。结果表明，在有葡萄糖存在的情况下，突触体中的线粒体能够维持202±8 mV（平均值±标准差）的跨膜电位，而突触体膜的电位为78±8 mV（平均值±标准差）。当使用损害线粒体能量代谢的麻醉剂浓度（0.6 - 1 mM丙泊酚、10 - 40 μM恩氟烷、30 - 50 μM异氟烷、8 - 15 μM氟烷）时，突触体跨膜电位得以维持，此外，随着麻醉剂浓度的增加，观察到摄取的TPP +略有增加。
