Lipton P
Department of Physiology, University of Wisconsin, Madison 53706.
J Neurosci Methods. 1989 May;28(1-2):147-54. doi: 10.1016/0165-0270(89)90019-8.
Mammalian brain glycogen is adequate to support oxidative metabolism for several minutes. The present studies were done primarily to develop the guinea pig hippocampal slice as a model for studying the function and regulation of that glycogen. Slice glycogen falls to 6 nmol/mg dry wt. during the first hour of incubation at 36 degrees C but during the next 3 h recovers to 20 nmol/mg dry wt., similar to in situ values. Glycogen concentration in the dentate gyrus molecular layer is double its value in the whole hippocampal slice, suggesting its distribution is related to metabolic demand. When both glucose and oxygen are removed from the medium, glycogen and ATP fall to 50% within 6 min. The glycogen fall is unaffected by prolonged calcium depletion or by 3-isobutyl 1-methylxanthine, an adenosine antagonist. It is markedly slowed by preincubating the slice with creatine, which also slows the fall in ATP. It is concluded that ATP breakdown and subsequent increased 5'-AMP is activating glycogen mobilization in this in vitro model of ischemia.
哺乳动物大脑中的糖原足以支持数分钟的氧化代谢。本研究主要是为了开发豚鼠海马切片，作为研究该糖原功能和调节的模型。切片糖原在36℃孵育的第一个小时内降至6 nmol/mg干重，但在接下来的3小时内恢复到20 nmol/mg干重，与原位值相似。齿状回分子层中的糖原浓度是整个海马切片中糖原浓度的两倍，这表明其分布与代谢需求有关。当培养基中的葡萄糖和氧气都被去除时，糖原和ATP在6分钟内降至50%。糖原的下降不受长时间钙耗竭或腺苷拮抗剂3-异丁基-1-甲基黄嘌呤的影响。通过用肌酸预孵育切片可显著减缓糖原下降，这也减缓了ATP的下降。结论是，在这个体外缺血模型中，ATP分解以及随后5'-AMP的增加正在激活糖原动员。
