Na+ imaging reveals little difference in action potential-evoked Na+ influx between axon and soma

被引:142
作者
Fleidervish, Ilya A. [1 ,2 ,3 ]
Lasser-Ross, Nechama [2 ,4 ]
Gutnick, Michael J. [2 ,3 ]
Ross, William N. [2 ,4 ]
机构
[1] Ben Gurion Univ Negev, Fac Hlth Sci, Dept Physiol, Beer Sheva, Israel
[2] Marine Biol Lab, Woods Hole, MA 02543 USA
[3] Hebrew Univ Jerusalem, Koret Sch Vet Med, IL-76100 Rehovot, Israel
[4] New York Med Coll, Dept Physiol, Valhalla, NY 10595 USA
基金
美国国家卫生研究院; 美国国家科学基金会; 以色列科学基金会;
关键词
NEOCORTICAL PYRAMIDAL NEURONS; CEREBELLAR PURKINJE NEURONS; PERSISTENT SODIUM CURRENT; INITIAL SEGMENT; SYNAPTIC EFFICACY; BASAL DENDRITES; OPTIC NERVES; CHANNELS; RAT; CALCIUM;
D O I
10.1038/nn.2574
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
In cortical pyramidal neurons, the axon initial segment (AIS) is pivotal in synaptic integration. It has been asserted that this is because there is a high density of Na+ channels in the AIS. However, we found that action potential-associated Na+ flux, as measured by high-speed fluorescence Na+ imaging, was about threefold larger in the rat AIS than in the soma. Spike-evoked Na+ flux in the AIS and the first node of Ranvier was similar and was eightfold lower in basal dendrites. At near-threshold voltages, persistent Na+ conductance was almost entirely axonal. On a time scale of seconds, passive diffusion, and not pumping, was responsible for maintaining transmembrane Na+ gradients in thin axons during high-frequency action potential firing. In computer simulations, these data were consistent with the known features of action potential generation in these neurons.
引用
收藏
页码:852 / U96
页数:11
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