COMPARATIVE ASPECTS OF IONIC CONDUCTANCES IN NERVE AND HEART CELL MEMBRANES

本课题是关于离子电流的比较分析 神经和心脏细胞膜中的通道以及它们之间的关系 两种制剂的兴奋性通道。 在过去一年， 最初的实验准备是鸡胚心脏细胞 和巨大的鱿鱼轴突 一个主要的发现是， 起搏电流成分（I-f）在单个鸡心脏细胞与 穿孔膜片钳电压钳技术。 这项技术让我们 在不损失细胞内因子的情况下记录If组分 已经被证明可以调节这个通道， 使用更传统的吸移管技术。 另一个主要 这一发现解决了一个关于离子渗透的悖论， 鱿鱼轴突中的延迟整流钾离子通道（I-K）。 的 （I-K）电流-电压关系对外部钾的依赖性 离子浓度是一致的--离子通过的独立运动 通道，这与（I-K）的示踪剂通量测量不一致。 后者的结果是一致的耦合运动的离子通过 频道。 我们开发了一个模型来解决这个悖论。

This project is concerned with a comparative analysis of ionic current channels in nerve and heart cell membranes and the relationship of these channels to excitability in both preparations. During the past year, the primary experimental preparations have been embryonic chick heart cells and giant squid axons. One major finding has been the observation of the pacemaker current component (I-f) in single chick heart cells with the perforated patch-clamp voltage-clamp technique. This technique allows us to record the If component without the loss of intracellular factors which have been shown to regulate this channel, and which may be lost using the more traditional suction pipette technique. Another major finding has been the resolution of a paradox concerning ion permeation of the delayed rectifier potassium ion channel, (I-K), in squid axons. The dependence of the (I-K) current-voltage relation on external potassium ion concentration is consistent-with independent movement of ions through the channel, which is at odds with tracer flux measurements from (I-K). The latter results are consistent with coupled movement of ions through the channel. We have developed a model which resolves this paradox.