Maturation of layer 5 neocortical pyramidal neurons:: amplifying salient layer 1 and layer 4 inputs by Ca2+ action potentials in adult rat tuft dendrites
Maturation of layer 5 neocortical pyramidal neurons:: amplifying salient layer 1 and layer 4 inputs by Ca2+ action potentials in adult rat tuft dendrites
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DOI：
10.1111/j.1469-7793.2000.00571.x
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发表时间：
2000-08-01
影响因子：
5.5
通讯作者：
Zhu, JJ
中科院分区：
文献类型：
--
作者：
Zhu, JJ
1．观察大鼠出生后2个月（出生后第2-56天）第5层皮质锥体细胞顶端树突簇的树枝化和电兴奋性的变化。2．充满生物胞素的神经元的 RT 结构表明，顶端树突干不断生长，变得更长更厚，簇之间的距离也越来越大。体细胞增加了5倍以上，3。在 P2 动物中，簇和体细胞都具有高输入电阻（> 500 M Omega），并且簇在电紧张方面接近某些。相反，P56神经元的顶端簇和胞体具有较低的输入电阻(<50M Omega)，并且它们彼此电隔离。 4．注入 P2 细胞簇的去极化电流脉冲产生的主要是短持续时间（类似于 15 ms）的 Na+ 依赖性再生树突电位，而在 P56 动物簇中，产生的复杂再生电位具有较长的持续时间（类似于 55 ms）并且依赖于 Na+ 和 Ca2+。在年轻和幼年动物(P14-28)中，树突再生电位可能限制顶端树突丛，而在成年动物(>P42)中，：复杂的再生电位经常与体细胞动作电位同时发生。5．通过方形脉冲电流注射和突触刺激进行测定，第 5 层锥体神经元的主要发育变化是树突簇与体细胞的渐进性电紧张隔离。这种变化伴随着复杂的、主要是 Na+- 和 Ca2+ 依赖性的、部分在簇中、部分在轴突中启动的再生树突电位的出现。通过活跃的树突 Na+ 和 Ca2+ 电导将树突簇和轴突起始区耦合起来以实现再生潜力，使成熟的第 5 层锥体神经元能够选择性地检测显着的远端突触输入和到达不同皮质层的一致突触输入。
1. Changes in the arborization and electrical excitability of the apical dendritic tufts of pyramidal cells of cortical layer 5 were examined during the first 2 months (postnatal days (P)2-56) of postnatal development in rats.2. Rt constructions of biocytin-filled neurons showed that the apical dendritic trunk was continually growing, becoming longer and thicker and that the distance between the tuft. and soma increased more than 5-fold,3. In P2 animals, both the tuft and soma had a high input, resistance (> 500 M Omega) and the tuft was electrotonically close to the some. In contrast, the apical tuft and soma of P56 neurons had a low input resistance (< 50 M Omega) and they were electrotonically isolated From each other.4. Depolarizing current pulses injected into the tuft of P2 cells generated mostly Na+-dependent regenerative dendritic potentials of short duration (similar to 15 ms) while in the tuft of P56 animals, complex regenerative potentials were generated which had a longer duration (similar to 55 ms) and were Na+ and Ca2+ dependent. In young and juvenile animals (P14-28) dendritic regenerative potentials could br restricted tu the apical dendritic tuft whereas in adult animals (> P42), the: complex regenerative potentials frequently occurred simultaneously wit ll somatic action potentials.5. The main developmental change in layer 5 pyramidal neurons, as assayed with square pulse current injections and synaptic stimulations, is the progressive electrotonic isolation of thr: dendritic tuft from the soma. This change is concomitant with that the appearance of complex, mostly Na+- and Ca2+-dependent, regenerative dendritic potentials initiated partly in the tuft and partly in the axon. The coupling of the dendritic tuft and axonal initiation zones for regenerative potentials by active dendritic Na+ and Ca2+ conductances enables mature layer 5 pyramidal neurons to detect selectively the salient distal synaptic inputs and coincident synaptic inputs arriving at different cortical layers.