Dendritic mechanisms underlying the coupling of the dendritic with the axonal action potential initiation zone of adult rat layer 5 pyramidal neurons
Dendritic mechanisms underlying the coupling of the dendritic with the axonal action potential initiation zone of adult rat layer 5 pyramidal neurons
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DOI：
10.1111/j.1469-7793.2001.0447a.x
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发表时间：
2001-06-01
影响因子：
5.5
通讯作者：
Sakmann, B
中科院分区：
文献类型：
--
作者：
Larkum, ME;Zhu, JJ;Sakmann, B
1.双，三倍和四倍的全细胞电压记录同时从不同部分的顶端树突状乔木和索马的成年第5层（L5）锥体神经元。我们研究了支持树突动作电位（AP）在树突和轴突AP起始区之间传导的膜机制及其对随后AP模式的影响.向远端树突起始区注入电流的持续时间控制了与轴突起始区的耦合程度和AP模式.远端诱发再生电位的两个组成部分是明显不同的：一个快速上升的峰值电位是TTS敏感的，一个缓慢上升的平台样电位是Cd 2+和Ni 2+敏感的，只在较长时间的电流注入下才出现.更快的前向传播的Na+依赖性成分的振幅和后向传播的AP的振幅分为两类（在前向传播的情况下更明显）。电流注入到枝晶中改变了两个方向的传播。体细胞电流注射，引起单一的Na+ AP诱发的Na+ AP的爆发时，电流同时注入近端顶端树突。其机制不依赖于树突状Na+-Ca 2 + AP.提出了一个L5锥体神经元的三室模型。它包括远端树突和轴突AP起始区和近端顶端树突。每个隔室都以不同的方式对AP放电的启动和模式做出贡献。输入到三个主要的树突乔木（簇状树突，顶端斜树突和基底树突）有一个占主导地位的影响，只有一个这些舱室。因此，L5锥体的AP模式反映了皮质柱中突触活动的层状分布。
1. Double, triple and quadruple whole-cell voltage recordings were made simultaneously from different parts of the apical dendritic arbor and the soma of adult layer 5 (L5) pyramidal neurons. We investigated the membrane mechanisms that support the conduction of dendritic action potentials (APs) between the dendritic and axonal AP initiation zones and their influence on the subsequent AP pattern.2. The duration of the current injection to the distal dendritic initiation zone controlled the degree of coupling with the axonal initiation zone and the AP pattern.3. Two components of the distally evoked regenerative potential were pharmacologically distinguished: a rapidly rising peak potential that was TTS sensitive and a slowly rising plateau-like potential that was Cd2+ and Ni2+ sensitive and present only with longer-duration current injection.4. The amplitude of the faster forward-propagating Na+-dependent component and the amplitude of the back-propagating AP fell into two classes (more distinctly in the forward-propagating case). Current injection into the dendrite altered propagation in both directions.5. Somatic current injections that elicited single Na+ APs evoked bursts of Na+ APs when current was injected simultaneously into the proximal apical dendrite. The mechanism did not depend on dendritic Na+-Ca2+ APs.6. A three-compartment model of a L5 pyramidal neuron is proposed. It comprises the distal dendritic and axonal AP initiation zones and the proximal apical dendrite. Each compartment contributes to the initiation and to the pattern of AP discharge in a distinct manner. Input to the three main dendritic arbors (tuft dendrites, apical oblique dendrites and basal dendrites) has a dominant influence on only one of these compartments. Thus, the AP pattern of L5 pyramids reflects the laminar distribution of synaptic activity in a cortical column.