Octeau J Christopher, Faas Guido, Mody Istvan, Khakh Baljit S
Department of Physiology, David Geffen School of Medicine, University of California Los Angeles;
Department of Neurology, David Geffen School of Medicine, University of California Los Angeles.
J Vis Exp. 2018 May 7(135):57511. doi: 10.3791/57511.
Potassium ions significantly contribute to the resting membrane potential of cells and, therefore, extracellular K concentration is a crucial regulator of cell excitability. Altered concentrations of extracellular K affect the resting membrane potential and cellular excitability by shifting the equilibria between closed, open and inactivated states for voltage-dependent ion channels that underlie action potential initiation and conduction. Hence, it is valuable to directly measure extracellular K dynamics in health and diseased states. Here, we describe how to make, calibrate and use monopolar K-selective microelectrodes. We deployed them in adult hippocampal brain slices to measure electrically evoked K concentration dynamics. The judicious use of such electrodes is an important part of the tool-kit needed to evaluate cellular and biophysical mechanisms that control extracellular K concentrations in the nervous system.
钾离子对细胞的静息膜电位有显著贡献，因此，细胞外钾浓度是细胞兴奋性的关键调节因子。细胞外钾浓度的改变会通过改变电压依赖性离子通道的关闭、开放和失活状态之间的平衡，从而影响静息膜电位和细胞兴奋性，而这些离子通道是动作电位起始和传导的基础。因此，直接测量健康和疾病状态下的细胞外钾动态变化具有重要价值。在此，我们描述了如何制作、校准和使用单极钾选择性微电极。我们将它们部署在成年海马脑片中，以测量电诱发的钾浓度动态变化。明智地使用此类电极是评估控制神经系统中细胞外钾浓度的细胞和生物物理机制所需工具包的重要组成部分。
