Glucose, Lactate and Glutamine but not Glutamate Support Depolarization-Induced Increased Respiration in Isolated Nerve Terminals
Glucose, Lactate and Glutamine but not Glutamate Support Depolarization-Induced Increased Respiration in Isolated Nerve Terminals
复制标题
DOI：
10.1007/s11064-016-2036-4
复制
发表时间：
2017-01-01
影响因子：
4.4
通讯作者：
Waagepetersen, Helle S.
中科院分区：
文献类型：
--
作者：
Hohnholt, Michaela C.;Andersen, Vibe H.;Waagepetersen, Helle S.
从不同年龄和基因修饰的实验动物制备的突触体构成了研究突触前机制的有价值的模型系统。从全脑分离突触体，并使用XFe 96细胞外通量分析仪（Seahorse Bioscience）研究在不同底物存在下的线粒体呼吸和糖酵解速率。通过将突触体依次暴露于ATP合成酶抑制剂寡霉素、解偶联剂FCCP（羰基氰-4-（三氟甲氧基）苯腙）和电子传递链抑制剂鱼藤酮和抗霉素A，检测线粒体功能。突触体以葡萄糖为底物，表现出强烈的呼吸活动。与1 mM葡萄糖相比，10 mM葡萄糖的FCCP依赖性呼吸显着更高。突触体也很容易使用丙酮酸作为底物，这提高了基础呼吸，活性依赖性呼吸诱导的藜芦碱和呼吸反应的解偶联相比，获得与葡萄糖作为底物。乳酸也被突触体用作底物，但与丙酮酸相反，线粒体乳酸介导的呼吸与使用葡萄糖作为底物的呼吸相当。使用谷氨酸和谷氨酰胺作为底物的突触体呼吸显著高于基础呼吸，而寡霉素依赖性和FCCP诱导的呼吸低于在葡萄糖作为底物的存在下获得的响应。我们提供的证据表明，突触体能够使用除了葡萄糖和丙酮酸也底物乳酸，谷氨酸和谷氨酰胺，以支持他们的基础呼吸。发现藜芦定增加由葡萄糖、丙酮酸盐、乳酸盐和谷氨酰胺支持的呼吸，并且发现FCCP增加由葡萄糖、丙酮酸盐和乳酸盐支持的呼吸。当谷氨酸是唯一的能量底物时，情况并非如此。
Synaptosomes prepared from various aged and gene modified experimental animals constitute a valuable model system to study pre-synaptic mechanisms. Synaptosomes were isolated from whole brain and the XFe96 extracellular flux analyzer (Seahorse Bioscience) was used to study mitochondrial respiration and glycolytic rate in presence of different substrates. Mitochondrial function was tested by sequentially exposure of the synaptosomes to the ATP synthase inhibitor, oligomycin, the uncoupler FCCP (carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone) and the electron transport chain inhibitors rotenone and antimycin A. The synaptosomes exhibited intense respiratory activity using glucose as substrate. The FCCP-dependent respiration was significantly higher with 10 mM glucose compared to 1 mM glucose. Synaptosomes also readily used pyruvate as substrate, which elevated basal respiration, activity-dependent respiration induced by veratridine and the respiratory response to uncoupling compared to that obtained with glucose as substrate. Also lactate was used as substrate by synaptosomes but in contrast to pyruvate, mitochondrial lactate mediated respiration was comparable to respiration using glucose as substrate. Synaptosomal respiration using glutamate and glutamine as substrates was significantly higher compared to basal respiration, whereas oligomycin-dependent and FCCP-induced respiration was lower compared to the responses obtained in the presence of glucose as substrate. We provide evidence that synaptosomes are able to use besides glucose and pyruvate also the substrates lactate, glutamate and glutamine to support their basal respiration. Veratridine was found to increase respiration supported by glucose, pyruvate, lactate and glutamine and FCCP was found to increase respiration supported by glucose, pyruvate and lactate. This was not the case when glutamate was the only energy substrate.