Two Populations of layer V pyramidal cells of the mouse neocortex:: Development and sensitivity to anesthetics
Two Populations of layer V pyramidal cells of the mouse neocortex:: Development and sensitivity to anesthetics
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DOI：
10.1152/jn.00076.2005
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发表时间：
2005-11-01
影响因子：
2.5
通讯作者：
Audinat, E
中科院分区：
文献类型：
--
作者：
Christophe, E;Doerflinger, N;Audinat, E
以往的研究表明，第V层锥体神经元投射到皮层下结构或对侧皮层经历不同的形态和电生理模式的发展在出生后的前三周。为了分离这种差异成熟的决定因素，我们分析了投射到上级丘（SC细胞）或对侧皮质（CC细胞）的第V层锥体神经元的基因表达和内在膜特性，通过结合全细胞记录和单细胞RT-PCR在出生后5-7天或P21-30岁小鼠制备的急性切片中。在测试的24个基因中，钙通道亚基α 1B和α 1C、蛋白酶Nexin 1和钙结合蛋白钙结合蛋白在成年SC和CC细胞中差异表达，钾通道亚基Kv4.3在发育的两个阶段优先在CC细胞中表达。固有的膜特性，包括输入电阻，振幅的超极化激活电流，和动作电位阈值，早在出生后的第一周，并持续整个成年期的两个人口之间的数量不同。然而，这两种细胞类型在所有发育阶段具有相似的规律动作电位放电行为。令人惊讶的是，当我们在断头前增加氯胺酮-甲苯噻嗪或戊巴比妥麻醉的持续时间时，一部分成熟的SC细胞，而不是CC细胞，激发了动作电位的爆发。总之，这些结果表明，这两个群体的第V层锥体神经元已经开始在出生后的第一周不同，并表现出不同的放电能力麻醉后。
Previous studies have shown that layer V pyramidal neurons projecting either to subcortical structures or the contralateral cortex undergo different morphological and electrophysiological patterns of development during the first three postnatal weeks. To isolate the determinants of this differential maturation, we analyzed the gene expression and intrinsic membrane properties of layer V pyramidal neurons projecting either to the superior colliculus (SC cells) or the contralateral cortex (CC cells) by combining whole cell recordings and single-cell RT-PCR in acute slices prepared from postnatal day (P) 5-7 or P21-30 old mice. Among the 24 genes tested, the calcium channel subunits alpha 1B and alpha 1C, the protease Nexin 1, and the calcium-binding protein calbindin were differentially expressed in adult SC and CC cells and the potassium channel subunit Kv4.3 was expressed preferentially in CC cells at both stages of development. Intrinsic membrane properties, including input resistance, amplitude of the hyperpolarization-activated current, and action potential threshold, differed quantitatively between the two populations as early as from the first postnatal week and persisted throughout adulthood. However, the two cell types had similar regular action potential firing behaviors at all developmental stages. Surprisingly, when we increased the duration of anesthesia with ketamine-xylazine or pentobarbital before decapitation, a proportion of mature SC cells, but not CC cells, fired bursts of action potentials. Together these results indicate that the two populations of layer V pyramidal neurons already start to differ during the first postnatal week and exhibit different firing capabilities after anesthesia.