Cerebral Protein Turnover: Aspects and Problems
Cerebral Protein Turnover: Aspects and Problems
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大脑蛋白质周转：方面和问题
DOI：
10.1007/978-94-011-1620-6_1
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
M. Banay‐Schwartz
中科院分区：
文献类型：
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作者：
A. Lajtha;D. Dunlop;M. Banay‐Schwartz
在过去的几十年里，我们对大脑蛋白质合成和降解机制、这些过程的代谢率以及改变这些代谢率的因素的看法和认识发生了重大变化。由于任务的复杂性，直到最近才对大脑进行这方面的研究。由于技术上的困难，例如标记氨基酸通过血脑屏障的速度有限，人们认为神经系统中的蛋白质周转非常缓慢或不存在，这是一个不合理的结论，考虑到大脑缺乏显著的再生能力，是永久信息（记忆）的场所。现在我们知道，蛋白质代谢在大脑中非常活跃，并参与许多关键功能，如神经肽的形成和酶的激活。合成和降解速率在发育和老化过程中都经历了许多变化，并可能受到病理和环境因素的影响。希望进一步了解所涉及的机制将开辟各种治疗和诊断的可能性。有了PET，现在有可能研究活体人脑中的蛋白质代谢，这是一种直到最近才梦想的可能性。多年来，我们研究了动物脑蛋白代谢的各个方面，在本章中，我们将简要回顾一些发现，讨论一些问题，并考虑这些对PET研究的影响。其中重要的问题是，大脑中蛋白质的代谢是否在重要方面与其他器官不同，以及关注脑蛋白质代谢的研究是否合理。饥饿是证明代谢反应差异的众多例子之一。饥饿动物的大部分身体组织都会遭受严重的蛋白质损失，但大脑不会。此外，血脑屏障的存在带来了许多技术问题，可能导致苯丙酮尿症，这是大脑和代谢率测量所特有的。最后，蛋白质合成率，像葡萄糖消耗一样，必须是活性和活性的一般指标
Our ideas and our knowledge about the mechanisms of cerebral protein synthesis and degradation, the metabolic rates of these processes, and the factors which alter these rates have undergone major changes in the past few decades. Because of the complexity of the task, brain has not been examined in this respect until comparatively recently. Due to the technical difficulties, such as the limited rates of access of labeled amino acids across the blood-brain barrier, it was thought that protein turnover is very slow or absent in the nervous system, a not unreasonable conclusion, considering that the brain lacks significant regenerative capacity and is the site of permanent information (memory). Now we know that protein metabolism is highly active in the brain and is involved in many crucial functions such as neuropeptide formation and enzyme activation. Both synthesis and degradation rates undergo numerous changes in development and aging, and they can be influenced by pathological and environmental factors. It is hoped that further knowledge of the mechanisms involved will open up a variety of therapeutic and diagnostic possibilities. With PET it may now be possible to study protein metabolism in the living human brain in vivo, a possibility only dreamed of till recently.We have examined various aspects of brain protein metabolism in animals for many years, and in this chapter we will briefly review some of the findings, discuss some of the problems, and consider what implications these have for PET studies. Among the important questions are whether the metabolism of protein in the brain is different in significant aspects from that of other organs, and whether studies focused on brain protein metabolism are justified. Starvation is one of a number of examples demonstrating differences in metabolic response. Most body tissues in starving animals suffer severe losses of protein, but not the brain. Also, the presence of the blood-brain barrier introduces a number of technical problems, and perhaps the disease phenylketonuria, which are specific to the brain and to measurements of metabolic rates therein. Finally protein synthesis rates, like glucose consumption, must be general indicators of the activity and