RESTING POTENTIAL IN NERVE MEMBRANE

我们建议将电生理测量和 放射性同位素通量测量以研究其控制机制 神经膜的静息电位。目前，非常 人们对休眠的运输机制知之甚少 电流(决定静息电势)。我们的预赛 研究表明，静息电位受一种 一种新型的电压门控休眠通道 来自延迟整流K通道的特性。具体的 这项拟议研究的目的是：(1)识别和 描述控制细胞周期的膜通路 静息状态下的膜电流；(2)彻底测试 现有的电扩散理论(即Goldman-Hodgkin-Katz (GHK方程)通过同时测量膜 电势、膜电导和膜透过率 作为离子浓度的函数。这些实验将是 在可兴奋离子通道和 离子泵受阻；(3)发展改进的理论 结合观测数据建立静息电势模型 静止通道在电磁场中的输运特性 扩散理论。我们希望这项研究能够为我们提供一个 更好的模型，可以更好地解释实验结果 比GHK方程更令人满意。 将使用鱿鱼巨型轴突作为主要的生物模型。 这种制剂有几个技术优势。例如, 使用内部灌流技术，内部和 轴突的外部离子环境可以随意控制。 单向同位素标记的离子通量也可以是 直接测量，几乎没有歧义。此外，这样的 测量可以在恒定的膜电位下进行，方法是 采用电压钳位和空间钳位。药物干预措施包括 可用于阻断可兴奋离子通道和离子泵。带着我们的 专门设计的仪器，多项实验 可以同时测量参数(例如，膜 在给定膜电位下的电导和42K外流)。是这样的 同步测量将使我们能够彻底测试 通过比较从不同角度获得的数据建立理论模型 方法：研究方法。

We propose to combine electrophysiological measurements and radioisotope flux measurements to study the control mechanisms of the resting potential of the nerve membrane. At present, very little is known about the transport mechanisms of the resting current (which determines the resting potential). Our preliminary studies have indicated that the resting potential is controlled by a new type of voltage-gated resting channel which differs in properties from the delayed rectifier K channel. The specific aims of this proposed research are: (1) To identify and to characterize the membrane pathways which control the membrane current at the resting state; (2) To thoroughly test the existing electro-diffusion theory (i.e. the Goldman-Hodgkin-Katz (GHK) equation) by simultaneously measuring membrane potential, membrane conductance and membrane permeabilities as a function of ionic concentrations. These experiments will be done under the condition that the excitable ionic channels and the ion pumps are blocked; (3) To develop an improved theoretical model of the resting potential by incorporating the observed transport properties of the resting pathways into the electro- diffusion theory. We hope this research will be able to provide a better model which will explain the experimental findings more satisfactorily than the GHK equation. The squid giant axon will be used as the primary biological model. This preparation has several technical advantages. For example, using an internal perfusion technique, both the internal and external ionic environment of the axon can be controlled at will. The unidirectional isotope-labelled ion fluxes can also be measured directly with little ambiguity. Furthermore, such measurements can be done at a constant membrane potential by using voltage-and space-clamp. Pharmacologic interventions are available to block excitable ion channels and ion pumps. With our specially designed apparatus, a number of experimental parameters can be measured simultaneously (e.g. membrane conductance and 42K efflux at a given membrane potential). Such simultaneous measurements will allow us to thoroughly test the theoretical model by comparing data obtained from different methods.