ACTIVATION OF HEXOSE MONOPHOSPHATE PATHWAY IN BRAIN BY ELECTRICAL STIMULATION IN VITRO
ACTIVATION OF HEXOSE MONOPHOSPHATE PATHWAY IN BRAIN BY ELECTRICAL STIMULATION IN VITRO
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体外电刺激激活脑内单磷酸己糖途径
DOI：
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发表时间：
1974
影响因子：
4.7
通讯作者：
K. Kuriyama
中科院分区：
文献类型：
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作者：
H. Kimura;K. Naito;K. Nakagawa;K. Kuriyama
摘要-在37°C下，将大脑皮层切片在Krebs‐Ringer‐tris（pH 7. 6）溶液中孵育15 min，[1 - 14 C]葡萄糖或[6 - 14 C]葡萄糖作为底物，产生的C-1：C-6 14 CO2比率为1. 21，而在施加电刺激（ES）后，该比率增加至3. 01。孵育15分钟后，6-磷酸葡萄糖酸（6PG）和6-磷酸葡萄糖（G6 P）（HMP途径的中间代谢物）的组织水平分别为7和180 nmol/g组织，在应用ES后分别增加了33%和45%。6-磷酸葡萄糖酸脱氢酶（6-PGDH，6-磷酸-d-葡萄糖酸：NADP+ 2-氧化还原酶，EC 1.1.1.44）和葡萄糖-6-磷酸脱氢酶（G6 PDH，d-葡萄糖-6-磷酸：NADP+ 1-氧化还原酶，EC 1.1.1.49）的活性是调节HMP途径活性的重要酶，在大脑皮层切片中分别为689和907 pmol/mg蛋白/min，通过应用ES分别增加了66%和25%。向反应混合物中加入40 mm-Na+可最大程度地激活突触体G6 PDH和6PGDH活性，而在微粒体G6 PDH和6PGDH中未观察到Na+激活。在电刺激脑组织中，异戊巴比妥对EM通路的抑制作用强于HMP通路，而丙咪嗪对HMP通路的抑制作用强于EM通路。
Abstract— The incubation of cerebral cortical slices for 15 min in Krebs‐Ringer‐tris (pH 7.6) solution at 37°C with [1‐14C]glucose or [6‐14C]glucose as substrates yielded a C‐1:C‐6 14CO2 ratio of 1.21, whereas this ratio increased to 3.01 after the application of electrical stimulation (ES). Tissue levels of 6‐phosphoglu‐conate (6PG) and glucose 6‐phosphate (G6P), intermediary metabolites of hexose monophosphate (HMP) pathway, were 7 and 180 nmol/g tissue following 15 min incubation, and increased by 33 and 45 per cent respectively following the application of ES. Activities of 6‐phosphogluconate dehydrogenase (6PGDH, 6‐phospho‐d‐gluconate: NADP+ 2‐oxidoreductase, EC 1.1.1.44) and glucose‐6‐phosphate dehydrogenase (G6PDH, d‐glucose‐6‐phosphate: NADP+ 1‐oxidoreductase, EC 1.1.1.49), important enzymes in regulating the activity of HMP pathway, in cerebral cortical slices were 689 and 907 pmol/mg protein/min and were increased by 66 and 25 per cent respectively by the application of ES. Synaptosomal G6PDH and 6PGDH activities were maximally activated by the addition of 40 mm‐Na+ to the reaction mixture, whereas no activation by Na+ was observed in microsomal G6PDH and 6PGDH. Amobarbital inhibited more strongly the Embden–Meyerhof (EM) pathway than the HMP pathway, while imipramine had a stronger inhibitory effect on HMP pathway than on EM pathway in the electrically stimulated cerebral tissues.