The cost of an action potential
The cost of an action potential
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DOI：
10.1016/s0165-0270(00)00308-3
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发表时间：
2000-11-30
影响因子：
3
通讯作者：
Bach-y-Rita, P
中科院分区：
文献类型：
--
作者：
Aiello, GL;Bach-y-Rita, P
神经元模块，或“细胞模块”。由数百万个相互连接的细胞组成的大脑被认为是大脑许多功能的基础，例如情绪、睡眠、饥饿、警惕等。根据模块的范围，细胞组装体中的神经通讯可能超过代谢资源。一个中等大小（10 000个神经元）的模块将需要至少10 J/1的大脑，根据计算的成本为10（11）-10（12）分子的ATP/cm（2）的细胞膜的孤立的动作电位（AP），与绝对最小值10（6）ATP在一个节点的兰维尔。这个数字与果蝇视网膜中大单极细胞的无髓鞘轴突去极化的成本相匹配。基于Na（+）和K（+）电导的突然变化的细胞膜的电路模型用于模拟AP并评估所产生的离子不平衡。AP的成本等同于为恢复细胞内K（+）的基于ATP的泵提供燃料所需的代谢能量。细胞组装的高代谢需求表明，可能涉及较便宜的神经通讯手段，如非突触扩散神经传递（NDN），这将符合大脑中空间和能量守恒定律。(C)2000 Elsevier Science B. V.保留所有权利。
Neuronal modules, or 'cell-assemblies'. comprising millions of mutually interconnected cells have been postulated to form the basis of many functions of the brain, such as mood, sleep, hunger, vigilance, and more. Depending on the extent of the module, neurocommunication in cell-assemblies might exceed metabolic resources. A medium-size (10 000 neurons) module would require at least 10 J per 1 of brain, based on a calculated cost of an isolated action potential (AP) of 10(11)-10(12) molecules of ATP per cm(2) of cell membrane, with an absolute minimum of 10(6) ATP at a node of Ranvier. The figure matches the cost of depolarizing the unmyelinated axon of the large monopolar cell in the blowfly retina. A circuit model of the cell membrane, based on abrupt changes of Na(+) and K(+) conductances, is used to emulate the AP and to assess the resulting ionic unbalance. The cost of an AP is equated to the metabolic energy necessary to fuel ATP-based pumps that restore intracellular K(+). The high metabolic demand of a cell-assembly suggests that less expensive means of neurocommunication may be involved, such as non-synaptic diffusion neurotransmission (NDN), which would comply with a proposed law of conservation of space and energy in the brain. (C) 2000 Elsevier Science B.V. All rights reserved.