Voltage-dependent ion channels controlling firing patterns of central neurons

联系PD/PI：Bean，Bruce P 项目摘要/摘要 这项拟议的研究的目标是了解多种类型的离子通道如何在 单个神经元共同作用，产生该神经元的放电模式。最终，我们希望利用这一点 开发离子通道靶向可差别化调节放电的药理制剂的知识 它可以治疗不同类型的神经元，从而治疗癫痫和共济失调等病理生理行为。 以前的资助阶段主要集中在钙通道、钠通道、Kv2、 和Kv4钾通道。下一个授权期的重点是了解不同的钾 通道组合来调节特定类型神经元的放电模式，以及抑制剂和 特定钾通道的增强剂不同地改变不同神经元的放电模式。我们 将跟进初步数据，显示BK和Kv3钾通道的抑制-包括通过 临床上使用的药物4-氨基吡啶通常会导致矛盾的射击速度减慢而不是加速。 我们将测试这一效应的两种可能机制：增强钠通道失活或重新招募 失活较慢的其他钾通道。一个关键要素是比较动作电位放电 在不同类型的神经元中。我们将重点介绍主要电生理表型的三个例子： 海马CA1区锥体神经元、小脑浦肯野神经元和中脑多巴胺神经元。 实验设计将动作电位放电的电流钳记录与电压相结合。 脑片完整神经元和急性分离神经元对基础电流的钳制分析 神经元，它允许快速电压钳在动作电位的快速时间尺度上研究门控。一个 该方法的主要特点将是在37℃时研究动作电位激发和通道门控动力学 °C电流钳位和电压钳位实验将通过动作电位钳直接相连 一种技术，其中自然激发行为的记录被用作电压钳位命令，以允许 对动作电位电流产生模式的成分进行药理学剖析。这个 研究将包括对阻断或增强的药理制剂的实质性表征 钾通道亚型，既可作为实验工具，也可作为临床药物的可能线索。 项目摘要/摘要第6页

Contact PD/PI: BEAN, BRUCE P Project Summary/ Abstract The goal of the proposed research is to understand how the many types of ion channels present in a single neuron work together to produce the firing patterns of that neuron. Ultimately, we hope to use this knowledge to develop ion channel-targeted pharmacological agents that can differentially regulate firing of different types of neurons and thereby treat pathophysiological behavior such as epilepsy and ataxias. Previous grant periods focused on the functional roles of calcium channels, sodium channels, Kv2, and Kv4 potassium channels. The focus in the next grant period is to understand how different potassium channels combine to regulate the firing patterns of specific types of neurons and how inhibitors and enhancers of particular potassium channels differentially modify firing patterns of different neurons. We will follow up preliminary data showing that inhibition of BK and Kv3 potassium channels – including by the clinically-used drug 4-aminopyridine - often causes paradoxical slowing rather than speeding of firing. We will test two possible mechanisms for this effect: enhanced inactivation of Na channels or recruitment of other potassium channels with slower deactivation. A key element is to compare action potential firing in different types of neurons. We will focus on three examples of major electrophysiological phenotypes: hippocampal CA1 pyramidal neurons, cerebellar Purkinje neurons, and midbrain dopamine neurons. The experimental design will combine current clamp recordings of action potential firing with voltage- clamp analysis of the underlying currents, using both intact neurons in brain slice and acutely dissociated neurons, which allow fast voltage clamp to study gating on the rapid time scale of the action potential. A key feature of the approach will be to study both action potential firing and channel gating kinetics at 37 °C. Current clamp and voltage clamp experiments will be directly linked by the action potential clamp technique, in which recordings of natural firing behavior are used as voltage clamp commands to allow pharmacological dissection of the components of current generating patterns of action potentials. The research will include substantial characterization of pharmacological agents that block or enhance potassium channel subtypes, both as experimental tools and as possible leads for clinical drugs. Project Summary/Abstract Page 6