Passive electrotonic properties of rat hippocampal CA3 interneurones
Passive electrotonic properties of rat hippocampal CA3 interneurones
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DOI：
10.1111/j.1469-7793.1999.743ab.x
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发表时间：
1999-03-15
影响因子：
5.5
通讯作者：
Jaffe, DB
中科院分区：
文献类型：
--
作者：
Chitwood, RA;Hubbard, A;Jaffe, DB
1.用全细胞膜片记录方法测定了CA 3中间神经元的线性膜反应。本研究中所有细胞的平均输入电阻（R-N）为526 +/- 16 M Ω，最慢的膜时间常数（tau（0））为73 +/- 3 ms。63个生物胞素标记的神经元的三维形态被用来构建房室模型。通过拟合线性膜响应估计比膜电阻率（R-m）和比膜电容（C-m）。获得了24个CA 3神经元的可接受拟合。平均R-m为61.9 +/- 34.2 Ohm cm（2），平均C-m为0.9 +/- 0.3 mu F cm（-2）。细胞内阻力（R-i）在本研究中无法解决.电压衰减的检查显示，从大多数树突突触输入位置到胞体的突触效率显着降低。兴奋性突触后电位（EPSP）的模拟进行了分析，在这两个网站的突触输入和索马。在沿着树突树的不同位置放置的突触输入在索马的去极化几乎没有变化。突触输入部位的EPSP幅值随着离索马的距离的增加而逐渐增大，这与输入阻抗的逐渐增大相一致。空间上不同的突触输入的“等效率”产生于两个相反的因素：从索马的距离突触EPSP振幅的增加是由一个几乎相等的电压衰减增加反对。这些模拟表明，在这些特定的神经元中，在索马测量的EPSP的幅度不会受到突触输入位置的显著影响。
1.The linear membrane responses of CA3 interneurones were determined with the use of whole-cell patch recording methods. The mean input resistance (R-N) for all cells in this study was 526 +/- 16 M Omega and the slowest membrane time constant (tau(0)) was 73 +/- 3 ms.2. The three-dimensional morphology of 63 biocytin-labelled neurones was used to construct compartmental models. Specific membrane resistivity (R-m) and specific membrane capacitance (C-m) were estimated by fitting the linear membrane response. Acceptable fits were obtained for 24 CA3 interneurones. The mean R-m was 61.9 +/- 34.2 Ohm cm(2) and the mean C-m was 0.9 +/- 0.3 mu F cm(-2). Intracellular resistance (R-i) could not be resolved in this study.3. Examination of voltage attenuation revealed a significantly low synaptic efficiency from most dendritic synaptic input locations to the soma.4. Simulations of excitatory postsynaptic potentials (EPSPs) were analysed at both the site of synaptic input and at the soma. There was little variability in the depolarization at the soma from synaptic inputs placed at different locations along the dendritic tree. The EPSP amplitude at the site of synaptic input was progressively larger with distance from the soma, consistent with a progressive increase in input impedance.5. The 'iso-efficiency' of spatially different synaptic inputs arose from two opposing factors: an increase in EPSP amplitude at the synapse with distance from the soma was opposed by a nearly equivalent increase in voltage attenuation. These simulations suggest that, in these particular neurones, the amplitude of EPSPs measured at the soma will not be significantly affected by the location of synaptic inputs.