THE SPREAD OF NA+ SPIKES DETERMINES THE PATTERN OF DENDRITIC CA2+ ENTRY INTO HIPPOCAMPAL-NEURONS
THE SPREAD OF NA+ SPIKES DETERMINES THE PATTERN OF DENDRITIC CA2+ ENTRY INTO HIPPOCAMPAL-NEURONS
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DOI：
10.1038/357244a0
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发表时间：
1992-05-21
期刊：
影响因子：
64.8
通讯作者：
ROSS, WN
中科院分区：
文献类型：
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作者：
JAFFE, DB;JOHNSTON, D;ROSS, WN
许多类型神经元的树突都含有电压依赖性Na+和Ca 2+电导，它们能产生动作电位（参见参考文献1）。这些尖峰的功能还没有很好地理解，但由尖峰刺激的Ca 2+内流可能会影响树突中的Ca 2+依赖过程。这些包括突触可塑性2，3，细胞毒性4和胞吐作用5。几条证据表明，树突尖峰发生在树突6-8的子区域内。为了研究海马锥体细胞树突棘波扩散的机制，我们用Fura-2（参考文献9）和新开发的Na+敏感染料（参考文献10）分别对Ca 2+和Na+内流进行了成像。我们的研究结果表明，Ca 2+进入树突是由Na+尖峰，积极侵入树突。有限的空间分布的Ca 2+进入似乎取决于树突中的Na+尖峰的传播，而不是在一个有限的分布的Ca 2+通道。此外，我们已经观察到一个活动依赖性的过程，调节入侵的尖峰到树突，并逐步限制Ca 2+进入更近端的树突状区域。
THE dendrites of many types of neurons contain voltage-dependent Na+ and Ca2+ conductances that generate action potentials (see ref. 1 for review). The function of these spikes is not well understood, but the Ca2+ entry stimulated by spikes probably affects Ca2+-dependent processes in dendrites. These include synaptic plasticity 2,3, cytotoxicity 4 and exocytosis 5. Several lines of evidence suggest that dendritic spikes occur within subregions of the dendrites 6-8. To study the mechanism that govern the spread of spikes in the dendrites of hippocampal pyramidal cells, we imaged Ca2+ entry with Fura-2 (ref. 9) and Na+ entry with a newly developed Na+-sensitive dye 10). Our results indicate that Ca2+ entry into dendrites is triggered by Na+ spikes that actively invade the dendrites. The restricted spatial distribution of Ca2+ entry seems to depend on the spread of Na+ spikes in the dendrites, rather than on a limited distribution of Ca2+ channels. In addition, we have observed an activity-dependent process that modulates the invasion of spikes into the dendrites and progressively restricts Ca2+ entry to more proximal dendritic regions.