GENETIC CONTROL OF MEMBRANE CURRENTS

这项拟议研究的长期目标是确定分子 兴奋性细胞膜载流机制的本质 研究它们在电学性质上发生的变化 当编码这些特性的基因被操纵时，就会产生细胞膜。这个 该项目的头三年将仅限于电生理。 钉螺神经节神经细胞胞膜的研究。这项研究 将分为两个阶段：(1)膜的生物物理性质 在这些电池中发现的电流将被检测，使用一个单一的大电极 允许对神经元进行内部透析的电压钳。电压 细胞内钙和氢的依赖性、动力学和敏感性 将测量每个膜电流的离子，但将测量钙通道 被最详细地研究。二价阳离子的选择性和封闭性 将完全表征蜗牛钙通道的特性，它的动力学和 将研究瞬时电流-电压关系。(2) 我们将分析神经元之间存在的膜特性。范围和 物种之间和类别之间的变异类型将被测量 同一物种中的神经元。这是一个受环境控制的组成部分 将在适应不同环境的蜗牛的神经元中寻找变异 温度和基因决定的变异将在 钉螺螺旋体的同基因株。这项研究不仅将提供一种 更准确地了解通常存在的一些电流 在神经、肌肉和分泌细胞中，但它也将奠定基础和 开发研究电学特性的遗传控制的技术 动物体内的膜，在那里可以方便地进行遗传学研究。

The long-range goal of the proposed research is to determine the molecular nature of the current-carrying mechanisms in the membranes of excitable cells by studying the variations that occur in the electrical properties of these membranes when the genes that code for these properties are manipulated. The first three years of this project will be limited to electrophysiological studies of the somal membranes of ganglion nerve cells of snails. The research will be divided into two phases: (1) The biophysical properties of the membrane currents found in these cells will be examined, using a single macroelectrode voltage clamp that allows internal dialysis of the neuron. The voltage dependencies, kinetics and sensitivity to intracellular calcium and hydrogen ions will be measured for each of the membrane currents, but the Ca channel will be studied in greatest detail. The selectivity and blocking of divalent cations of the snail Ca channel will be completely characterized, and its kinetics and instantaneous current-voltage relations will be studied. (2) The variations in membrane properties that exist between neurons will be analyzed. The extent and types of variation will be measured between species and between classes of neurons in one species. An environmentally controlled component of this variation will be looked for in neurons from snails acclimated to different temperatures, and genetically determined variation will be sought between isogenic strains of the snail Helisoma. Not only will this research provide a more precise understanding of a number of currents which are generally present in nerve, muscle and secretory cells, but it will also lay the foundation and develop techniques for studying the genetic control of electrical properties of membranes in animals where genetic studies are conveniently done.