Energy-Efficient Action Potentials in Hippocampal Mossy Fibers
Energy-Efficient Action Potentials in Hippocampal Mossy Fibers
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DOI：
10.1126/science.1174331
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发表时间：
2009-09-11
期刊：
影响因子：
56.9
通讯作者：
Geiger, Joerg R. P.
中科院分区：
文献类型：
--
作者：
Alle, Henrik;Roth, Arnd;Geiger, Joerg R. P.
无髓鞘轴突的动作电位被认为对活动依赖性脑代谢有重要贡献。本研究表明，在大鼠海马无髓苔藓纤维的动作电位中，快速的Na+电流衰减和延迟的K+电流开始使它们各自的离子通量重叠最小化。这导致总Na+内流和每个动作电位的相关能量需求仅为理论最小值的1.3倍，而之前神经活动的能量预算计算中使用的因子为4。离子电导参数分析表明，Na+和K+通道的特性相匹配，使轴突动作电位节能，最大限度地减少它们对活性依赖性代谢的贡献。
Action potentials in nonmyelinated axons are considered to contribute substantially to activity-dependent brain metabolism. Here we show that fast Na+ current decay and delayed K+ current onset during action potentials in nonmyelinated mossy fibers of the rat hippocampus minimize the overlap of their respective ion fluxes. This results in total Na+ influx and associated energy demand per action potential of only 1.3 times the theoretical minimum, in contrast to the factor of 4 used in previous energy budget calculations for neural activity. Analysis of ionic conductance parameters revealed that the properties of Na+ and K+ channels are matched to make axonal action potentials energy-efficient, minimizing their contribution to activity-dependent metabolism.