INACTIVATION OF DELAYED RECTIFIER POTASSIUM CHANNELS

可兴奋细胞中的电压门控“延迟整流”钾通道对于动作电位期间膜的快速复极化非常重要。延迟整流器在维持去极化的过程中缓慢失活，然而(在某些情况下)失活在一系列类似动作电位的脉冲期间发展得相当快。失活的时间和电压依赖性深刻地影响神经元的行为，并可能与许多神经疾病有关，这些疾病涉及神经元的异常兴奋性，如癫痫。这项工作有三个具体的目标：(1)确定在特定的延迟整流Kv2.1中可能发生的几种类型的失活的性质和程度，(2)确定Kv2.1中的失活与门控是如何耦合的，以及(3)将这些信息应用于丘脑神经元中天然延迟整流的研究。这些目标将通过在转导Kv2.1的培养的HEK293细胞中进行全细胞电压钳记录(目标1和2)或在急性分离的大鼠丘脑腹基底部神经元(目标3)中实现。这些实验将对我们理解离子通道功能的机制以及该功能对神经元活动的贡献的长期目标做出重大贡献。

Voltage gated "delayed rectifier" potassium channels in excitable cells are important for rapid repolarization of the membrane during an action potential. Delayed rectifiers slowly inactivate during maintained depolarization, however (in some cases) inactivation develops quite rapidly during a train of action potential-like pulses. The time- and voltage-dependence of inactivation profoundly affects the behavior of a neuron, and could potentially be related to a number of neurological disorders that involve abnormal neuronal excitability, such as epilepsy. There are three specific aims of this work: (1) to determine the nature and extent of several types of inactivation that may occur in a particular delayed rectifier, Kv2.1, (2) to determine how inactivation is coupled to gating in Kv2.1, and (3) to apply that information to the study of native delayed rectifiers in thalamic neurons. Those aims will be accomplished by conducting whole cell voltage clamp recordings in cultured HEK293 cells transfected with Kv2.1 (Aims 1 and 2), or in acutely dissociated ventrobasal thalamic neurons from rat (Aim 3). These experiments will contribute significantly to our long-term objectives of understanding both the mechanism of ion channel function and the contribution of that function to neuronal activity.