Early development of voltage-gated ion currents and firing properties in neurons of the mouse cerebral cortex
Early development of voltage-gated ion currents and firing properties in neurons of the mouse cerebral cortex
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DOI：
10.1152/jn.00972.2002
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发表时间：
2003-04-01
影响因子：
2.5
通讯作者：
Moody, WJ
中科院分区：
文献类型：
--
作者：
Bahrey, HLP;Moody, WJ
从胚胎第14天到出生后第17天的小鼠大脑皮层急性切片进行电压和电流钳记录。我们的目标细胞迁移人口的胚胎中间区（IZ）和深层的胚胎和出生后皮质板（CP）。IZ神经元在整个胚胎期保持相当一致的特性，都表达高输入电阻、内向Na+电流和外向K+电流，并且没有显示任何超极化激活电流。在CP神经元中，在胚胎晚期和出生后早期发生了几种生理特性的变化：内向Na+电流密度强烈上调，而外向K+电流密度几乎保持不变，输入电阻急剧下降，并出现类似I-H的超极化激活电流。由于这些变化，动作电位变得更大，持续时间更短，其阈值向更负的电位移动。此外，CP细胞变得能够重复放电，并且越来越多的部分显示自发动作电位。这种离子通道特性的协调发展可能有助于确定未成熟皮质中发育相关自发活动的发生时间。
Voltage- and current-clamp recordings were made from acute slices of mouse cerebral cortex from embryonic day 14 to postnatal day 17. We targeted cells in the migratory population of the embryonic intermediate zone (IZ) and in deep layers of embryonic and postnatal cortical plate (CP). IZ neurons maintain fairly consistent properties through the embryonic period, all expressing high-input resistance, inward Na+ currents and outward K+ currents, and none showing any hyperpolarization-activated currents. In CP neurons, several changes in physiological properties occur in the late embryonic and early postnatal period: inward Na+ current density is strongly upregulated while outward K+ current density remains almost unchanged, input resistance drops dramatically, and a hyperpolarization-activated current resembling I-h appears. As a result of these changes, the action potential becomes larger, shorter in duration, and its threshold shifts to more negative potentials. In addition, CP cells become capable of firing repetitively and an increasing fraction show spontaneous action potentials. This coordinated development of ion channel properties may help to time the occurrence of developmentally relevant spontaneous activity in the immature cortex.