Participation of sodium currents in burst generation and control of membrane excitability in mesencephalic trigeminal neurons
Participation of sodium currents in burst generation and control of membrane excitability in mesencephalic trigeminal neurons
复制标题
DOI：
10.1523/jneurosci.5274-05.2006
复制
发表时间：
2006-03-29
影响因子：
5.3
通讯作者：
Chandler, SH
中科院分区：
文献类型：
--
作者：
Enomoto, A;Han, JM;Chandler, SH
阈下钠电流对于塑造神经元放电很重要，并且与中脑三叉神经元（Mes V）阈下膜振荡和爆发生成的产生和/或维持有关。此外，最近的数据表明，在一些中枢神经系统神经元中，复苏的钠电流有助于产生高频突发放电。在本研究中，我们试图使用动作电位钳法更直接地确定这些电流在 Mes V 电发生过程中的参与。在出生后第8-14天的大鼠中，使用全细胞膜片钳方法通过减法记录钠电流，以响应在电压钳模式下应用TTX，使用动作电位波形作为命令方案。我们发现，与 h 电流 (I-h) 和钙电流相比，TTX 敏感的钠电流是峰间间隔期间流动的主要内向电流。此外，除了动作电位上升期间流动的瞬态钠电流之外，我们还表明，复活的钠电流在后超极化的峰值处流动，而持续的钠电流在尖峰间期的中间流动以驱动高频放电。此外，瞬态、复活和持续的钠电流分量表现出电压和时间依赖性的缓慢失活，表明这些电流的缓慢失活可能有助于突发终止。数据表明钠电流的这些成分在 Mes V 神经元电发生中发挥着重要作用。
Subthreshold sodium currents are important in sculpting neuronal discharge and have been implicated in production and/or maintenance of subthreshold membrane oscillations and burst generation in mesencephalic trigeminal neurons (Mes V). Moreover, recent data suggest that, in some CNS neurons, resurgent sodium currents contribute to production of high-frequency burst discharge. In the present study, we sought to determine more directly the participation of these currents during Mes V electrogenesis using the action potential clamp method. In postnatal day 8 - 14 rats, the whole-cell patch-clamp method was used to record sodium currents by subtraction in response to application of TTX in voltage-clamp mode using the action potential waveform as the command protocol. We found that TTX-sensitive sodium current is the main inward current flowing during the interspike interval, compared with the h-current (I-h) and calcium currents. Furthermore, in addition to the transient sodium current that flows during the upstroke of action potential, we show that resurgent sodium current flows at the peak of afterhyperpolarization and persistent sodium current flows in the middle of the interspike interval to drive high-frequency firing. Additionally, transient, resurgent, and persistent sodium current components showed voltage- and time-dependent slow inactivation, suggesting that slow inactivation of these currents can contribute to burst termination. The data suggest an important role for these components of the sodium current in Mes V neuron electrogenesis.