Distribution and activation of voltage-gated potassium channels in cell-attached and outside-out patches from large layer 5 cortical pyramidal neurons of the rat
Distribution and activation of voltage-gated potassium channels in cell-attached and outside-out patches from large layer 5 cortical pyramidal neurons of the rat
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DOI：
10.1111/j.1469-7793.2000.t01-2-00611.x
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发表时间：
2000-06-15
影响因子：
5.5
通讯作者：
Bekkers, JM
中科院分区：
文献类型：
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作者：
Bekkers, JM
1.在大鼠感觉运动皮层急性切片（22-25 ℃）中，研究了来自大的第5层锥体神经元的索马体和初级顶树突的细胞贴附和外向贴片中的电压门控钾通道.包围的平均值显示，一些补丁只包含快速，I-A-样通道，其他只包含I-K-样通道，没有激活或失活缓慢，其余的包含两种通道类型的混合物。I-A和I-K通道的平均单位电导分别为8.5和20.3 pS，并且具有独特的门控模式。整体平均电流的峰值激活曲线由Boltzmann方程描述，其中半最大电压（V-1/2）和斜率因子（k）值对于I-A为-24.5 mV和16.9 mV，对于I-K为-7.6 mV和10.1 mV（贴片距离索马250 μ m）。I-A的稳态失活曲线给出的V-1/2和k值分别为-72.3 mV和-5.9 mV（距离索马250 μ m）。这些值与来自相同细胞类型的有核斑的I-A和I-K的相应数据相似。斑块中I-A和I-K的含量与沿着初级顶树突到索马体的距离呈弱相关。I-A的振幅平均每100 μ m增加2.3 pA，而I-K的振幅每100 μ m减少0.4 pA。树突状细胞附着的贴片中的I-A和I-K通道通过反向传播动作电位通过贴片电极的尖端而被激活。这些结果直接表明，这些钾通道参与动作电位复极化，从而有助于这些神经元的突触整合过程。
1. Voltage-gated potassium channels were studied in cell-attached and outside-out patches from the soma and primary apical dendrite of large layer 5 pyramidal neurons in acute slices of rat sensorimotor cortex (22-25 degrees C).2. Ensemble averages revealed that some patches contained only fast, I-A-like channels, others contained only I-K-like channels that did not inactivate or inactivated slowly, and the remainder contained mixtures of both channel types. I-A and I-K channels had mean unitary conductances of 8.5 and 20.3 pS, respectively, and had distinctive patterns of gating.3. Peak activation curves for ensemble-averaged currents were described by the Boltzmann equation with half-maximal voltage (V-1/2) and slope factor (k) values of -24.5 mV and 16.9 mV for I-A and -7.6 mV and 10.1 mV for I-K (patches 250 mu m from the soma). The steady-state inactivation curve for I-A gave V-1/2 and k values of -72.3 mV and -5.9mV ( 250 mu m from the soma). These values were similar to the corresponding data for I-A and I-K in nucleated patches from the same cell type.4. The amount of I-A and I-K present in patches depended weakly on distance along the primary apical dendrite from the soma. The amplitude of I-A increased, on average, by 2.3 pA per 100 mu m, while the amplitude of I-K decreased by 0.4 pA per 100 mu m.5. I-A and I-K channels in dendritic cell-attached patches were activated by the passage of a back-propagating action potential past the tip of the patch electrode. These results show directly that these potassium channels participate in action potential repolarisation, and thus contribute to the process of synaptic integration in these neurons.