GROUPINGS OF NONPYRAMIDAL AND PYRAMIDAL CELLS WITH SPECIFIC PHYSIOLOGICAL AND MORPHOLOGICAL-CHARACTERISTICS IN RAT FRONTAL-CORTEX
GROUPINGS OF NONPYRAMIDAL AND PYRAMIDAL CELLS WITH SPECIFIC PHYSIOLOGICAL AND MORPHOLOGICAL-CHARACTERISTICS IN RAT FRONTAL-CORTEX
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DOI：
10.1152/jn.1993.69.2.416
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发表时间：
1993-02-01
影响因子：
2.5
通讯作者：
KAWAGUCHI, Y
中科院分区：
文献类型：
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作者：
KAWAGUCHI, Y
1.本研究采用全细胞、电流钳技术，结合26-27 ℃下biocytin细胞内染色技术，研究了出生后16-22天大鼠额叶皮层第V层非锥体细胞和锥体细胞的生理和形态学特性。对输入电阻的半幅峰宽绘图显示两个生理类别的非锥体细胞。一类（n = 29）细胞的输入电阻小于400 MOMEGA，半幅峰宽小于0.8 ms;另一类（n = 22）细胞的输入电阻大于400 MOMEGA，半幅峰宽大于0.8 ms。根据其峰电位发放特性，前者称为快峰电位（FS）细胞，后者称为低阈值峰电位（LTS）细胞. FS细胞的静息电位较LTS细胞负。LTS细胞的膜时间常数是FS细胞的4倍。FS细胞的动作电位后超极化（Afterhyperpolarizations，AHPs）由单一成分组成，而LTS细胞的动作电位后超极化（Afterhyperpolarizations，AHPs）由早、晚两个峰组成。FS细胞的AHPs比LTS细胞的AHPs的早期成分具有更快的达峰时间和更大的幅度.在LTS细胞的超极化电位下，去极化电流脉冲可引起低阈值峰电位，而FS细胞则无。LTS细胞的低阈锋电位可被突触电位激活.去极化电流脉冲在FS细胞中诱发的锋电位序列几乎不表现出锋电位频率适应性，而在LTS细胞中诱发的锋电位序列表现出适应性.兴奋性突触后电位（EPSP）的两组非锥体细胞含有N-甲基-D-天冬氨酸（NMDA）受体介导的组件。刺激诱导的EPSPs与去极化的组合引起FS细胞的重复放电，这被NMDA受体阻滞剂废除。在这些条件下，在LTS细胞中没有观察到重复放电。两类非锥体细胞的染色体大小相似。FS细胞形态均为多极型，LTS细胞则兼有多极型和双簇型。一些FS细胞的树突延伸到第II/III层，但也有其他FS细胞的树突限制在第V层。LTS细胞的树突大多限制在第V层。FS细胞的树突大多是光滑的，但LTS细胞的树突具有适度但一致的棘群。FS细胞的神经支配更密集的区域相邻的胞体，和他们的轴突分支走更水平无论是在同一深度或以上的胞体。LTS细胞延伸轴突更垂直的层I和在某些情况下也到更深的层。第V层锥体细胞按其体积大小和输入阻力分为两类。一组[高输入阻力（HR）锥体细胞]的染色体直径为< 16 mum and input resistances >400 M Ω。另一种[低输入电阻（LR）锥体细胞]胞体> 17 μ m，输入电阻
1. Physiological and morphological Properties of layer V nonpyramidal and pyramidal cells in isolated slices of frontal cortex from young rats ( 16-22 days postnatal) were studied by whole-cell, current-clamp recording of visualized cell bodies coupled with intracellular staining by biocytin at 26-27-degrees-C.2. Plotting of spike width at half amplitude against input resistance revealed two physiological categories of nonpyramidal cells. One class (n = 29) had input resistances lower than 400 MOMEGA and spike widths at half amplitude shorter than 0.8 ms; the other (n = 22) had input resistances higher than 400 MOMEGA and spike widths longer than 0.8 ms. According to their spike firing characteristics, the former are called fast-spiking (FS) cells, and the latter low-threshold spike (LTS) cells.3. Resting potentials were more negative in FS cells than in LTS cells. Membrane time constants in LTS cells were four times larger than those of FS cells. Afterhyperpolarizations (AHPs) following action potentials consisted of a single component in FS cells, but two components with early and late peaks were observed in LTS cells. AHPs of FS cells had faster time-to-peak and larger amplitude than the early component of the AHPs of LTS cells.4. Low-threshold spikes induced by depolarizing current pulses were observed at hyperpolarized potentials in LTS cells, but not in FS cells. The low-threshold spikes in LTS cells could be activated at hyperpolarized potentials by synaptic potentials.5. Spike trains elicited by depolarizing current pulses in FS cells showed almost no spike-frequency adaptation, whereas those in LTS cells showed adaptation.6. Excitatory postsynaptic potentials (EPSPs) of both groups of nonpyramidal cells contained N-methyl-D-aspartate (NMDA) receptor-mediated components. A combination of stimulation-induced EPSPs with depolarization caused repetitive firing in FS cells that was abolished by NMDA receptor blockers. Repetitive firing was not observed in LTS cells under these conditions.7. The somal size of the two classes of nonpyramidal cells was similar. FS cells were all multipolar in shape, whereas LTS cells included both multipolar and bitufted types. The dendrites of some FS cells extended up into layers II/III, but there-were also other FS cells with their dendrites restricted in layer V. Dendrites of LTS cells were mostly restricted to layer V. Dendrites of FS cells were mostly smooth, but those of LTS cells possessed a modest but consistent population of spines.8. FS cells innervated more densely in areas adjacent to the somata, and their axonal branches ran more horizontally either at the same depth as or above their somata. LTS cells extended axons more vertically up to layer I and in some cases also to deeper layers.9. Pyramidal cells in layer V were divided into two groups by their somatic size and input resistance. One group [high input-resistance (HR) pyramidal cells] had somal diameters < 16 mum and input resistances >400 MOMEGA. The other [low input-resistance (LR) pyramidal cells] had somata > 17 mum and input resistance