Bielenberg G W, Hayn C, Krieglstein J
Biochem Pharmacol. 1986 Aug 15;35(16):2693-702. doi: 10.1016/0006-2952(86)90177-2.
The effects of different cerebro-protective agents on selected key enzymes of the energy metabolism of rat primary glial cultures and rat cerebral cortex were studied. As indicators for the capacity of the most important pathways of energy metabolism the following enzyme activities were determined: hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK), lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G-6-P-DH), malate dehydrogenase (MDH), glutamate dehydrogenase (GDH), and cytochrome-c-reductase (CCR). After a one week growth period, rat glial cultures were incubated for 3 or 4 weeks with the substances to be tested. Bencyclane (5 X 10(-5) mol/l) increased the activities of HK, G-6-P-DH, and LDH, whereas PFK and CCR were reduced. Pyritinol (10(-4) mol/l) led to a higher G-6-P-DH activity, simultaneously lowering the values for PFK, CCR, PK, LDH, and MDH. Under the influence of an extract of the leaves of Ginkgo bilobae (EGB; 100 mg/l) PFK, LDH, and MDH activities were reduced. All these alterations in enzyme activities went along with simultaneous reductions in protein content, therefore not allowing to exclude toxic effects with regard to the doses used. Moreover, direct interference with the analytical procedure was demonstrable for bencyclane and EGB. Piracetam (10(-3) mol/l), flunarizine (10(-6) mol/l), dihydroergocristine (5 X 10(-6) mol/l), and nicergoline (5 X 10(-6) mol/l) failed to induce any alteration in the employed doses. The most striking effects were obtained with meclofenoxate which was tested at 10(-3) and 10(-4) mol/l. The higher dose caused an elevation of HK, PFK, CCR, G-6-P-DH, GDH and MDH activities, while slightly reducing PK. With the lower dose of meclofenoxate CCR and G-6-P-DH activities were increased. Short-term incubation of the cultures with 10(-3) mol/l meclofenoxate for 24 hr led to an increase in LDH, G-6-P-DH, and GDH activities. Chronic incubation with meclofenoxate (10(-3) mol/l) followed by 48 hr deprivation of the drug resulted in elevated HK, PFK, CCR, G-6-P-DH, GDH, and MDH activities. These changes were accompanied by alterations in related metabolite levels. These include elevations in the concentration of creatine phosphate and fructose-1,6-bisphosphate, whereas glucose-6-phosphate levels were reduced. After one week of meclofenoxate deprivation the activities of CCR and G-6-P-DH were still elevated. The metabolites of meclofenoxate dimethylaminoethanol (DMAE; 10(-3) mol/l) and p-chlorophenoxyacetic acid (10(-3) mol/l) were also investigated.(ABSTRACT TRUNCATED AT 400 WORDS)
研究了不同脑保护剂对大鼠原代神经胶质细胞培养物和大鼠大脑皮层能量代谢相关关键酶的影响。作为能量代谢最重要途径能力的指标，测定了以下酶活性：己糖激酶（HK）、磷酸果糖激酶（PFK）、丙酮酸激酶（PK）、乳酸脱氢酶（LDH）、葡萄糖-6-磷酸脱氢酶（G-6-P-DH）、苹果酸脱氢酶（MDH）、谷氨酸脱氢酶（GDH）和细胞色素c还原酶（CCR）。在一周的生长周期后，将大鼠神经胶质细胞培养物与待测物质一起孵育3或4周。苄环烷（5×10⁻⁵mol/L）可增加HK、G-6-P-DH和LDH的活性，而PFK和CCR的活性降低。脑复新（10⁻⁴mol/L）使G-6-P-DH活性升高，同时降低PFK、CCR、PK、LDH和MDH的值。在银杏叶提取物（EGB；100mg/L）的影响下，PFK、LDH和MDH的活性降低。所有这些酶活性的改变都伴随着蛋白质含量的同时降低，因此无法排除所用剂量的毒性作用。此外，对于苄环烷和EGB，可证明其对分析程序有直接干扰。吡拉西坦（10⁻³mol/L）、氟桂利嗪（10⁻⁶mol/L）、双氢麦角汀（5×10⁻⁶mol/L）和尼麦角林（5×10⁻⁶mol/L）在所使用的剂量下未引起任何改变。在10⁻³和10⁻⁴mol/L测试的甲氯芬酯产生了最显著的效果。较高剂量使HK、PFK、CCR、G-6-P-DH、GDH和MDH的活性升高，同时使PK略有降低。较低剂量的甲氯芬酯可增加CCR和G-6-P-DH的活性。将培养物与10⁻³mol/L甲氯芬酯短期孵育24小时导致LDH、G-6-P-DH和GDH活性增加。用甲氯芬酯（10⁻³mol/L）长期孵育，随后48小时停药，导致HK、PFK、CCR、G-6-P-DH、GDH和MDH活性升高。这些变化伴随着相关代谢物水平的改变。这些包括磷酸肌酸和果糖-1,6-二磷酸浓度的升高，而葡萄糖-6-磷酸水平降低。在停用甲氯芬酯一周后，CCR和G-6-P-DH的活性仍然升高。还研究了甲氯芬酯的代谢产物二甲基氨基乙醇（DMAE；10⁻³mol/L）和对氯苯氧乙酸（10⁻³mol/L）。
