Voltage and calcium transients in basal dendrites of the rat prefrontal cortex
Voltage and calcium transients in basal dendrites of the rat prefrontal cortex
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DOI：
10.1113/jphysiol.2007.142315
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发表时间：
2007-12-01
影响因子：
5.5
通讯作者：
Antic, Srdjan D.
中科院分区：
文献类型：
--
作者：
Milojkovic, Bogdan A.;Zhou, Wen-Liang;Antic, Srdjan D.
高级皮质功能（感知、认知、学习和记忆）在很大程度上基于新皮质锥体细胞细树突分支中发生的电信号和钙信号的整合（突触整合）。薄基底树突中突触整合的机制很大程度上尚未被探索。我们使用最近开发的技术，即多位点电压钙成像，来比较沿单个树突分支的多个位置的电压和钙瞬变。我们的结果揭示了在阈上谷氨酸突触输入期间触发和塑造树突钙动力学和钙分布的特征电瞬变（平台电位）。我们定期观察到同一树突分支的三个不同区域同时发生三类电压-钙相互作用：（1）邻近输入位点，（2）在输入位点，以及（3）远离输入位点。距突触输入位点一百微米，无论是近端还是远端，树突钙瞬变都与树突平台电位在时间上紧密相关。然而，在同一树突上，在兴奋性输入的位置，钙瞬变比局部树突平台电位长几倍。这些 Ca2+ 平台（持续时间 0.5-2 秒）在空间上仅限于突触输入位点，在那里它们会导致树突兴奋性短暂下调。 Ca2+ 平台不是由细胞内储存的 Ca2+ 释放介导的，而是由 NMDA 依赖性小幅度去极化介导的，这种去极化在树突平台电位崩溃后持续存在。树突电压和钙分布的这些独特特征可以为沿同一基底分支的突触接触的同时长期（双向）调节提供不同的区域。
Higher cortical functions (perception, cognition, learning and memory) are in large part based on the integration of electrical and calcium signals that takes place in thin dendritic branches of neocortical pyramidal cells (synaptic integration). The mechanisms underlying the synaptic integration in thin basal dendrites are largely unexplored. We use a recently developed technique, multisite voltage-calcium imaging, to compare voltage and calcium transients from multiple locations along individual dendritic branches. Our results reveal characteristic electrical transients (plateau potentials) that trigger and shape dendritic calcium dynamics and calcium distribution during suprathreshold glutamatergic synaptic input. We regularly observed three classes of voltage-calcium interactions occurring simultaneously in three different zones of the same dendritic branch: (1) proximal to the input site, (2) at the input site, and (3) distal to the input site. One hundred micrometers away from the synaptic input site, both proximally and distally, dendritic calcium transients are in tight temporal correlation with the dendritic plateau potential. However, on the same dendrite, at the location of excitatory input, calcium transients outlast local dendritic plateau potentials by severalfold. These Ca2+ plateaus (duration 0.5-2 s) are spatially restricted to the synaptic input site, where they cause a brief down-regulation of dendritic excitability. Ca2+ plateaus are not mediated by Ca2+ release from intracellular stores, but rather by an NMDA-dependent small-amplitude depolarization, which persists after the collapse of the dendritic plateau potential. These unique features of dendritic voltage and calcium distributions may provide distinct zones for simultaneous long-term (bidirectional) modulation of synaptic contacts along the same basal branch.