ION TRANSPORT & ITS REGULATION IN PROXIMAL RENAL TUBULES

离子迁移的机制和几种离子迁移剂对离子迁移的影响 神经递质将与电生理技术研究， 兔近端小管的离体灌注段（S1、S2、S3）。 实验设计1）确定顶端的被动特性 和基底外侧膜和细胞旁通路，通过测量a） 跨上皮电阻，B）顶侧与基底侧的表观比率 膜电阻和c）细胞膜电位。 这些数据将 让我们计算等效电阻， 细胞膜的电动势。 离子取代将是 用于确定电池的离子扩散渗透性 膜。 2)为了研究去甲肾上腺素，多巴胺， 乙酰胆碱和其他物质，改变流体重吸收的 细胞膜的被动特性。 3)为了确定稳态 细胞内活性的Na，K和Cl，通过使用离子敏感 微电极以限定上坡和下坡运输过程， 确定在给定膜处的被动离子转运是否可以 电扩散的 如果这些实验成功， 活动测量将应用于研究的机制， 调节液体运输的神经递质的作用。 这些 实验应提供更好的了解近端小管 功能和整个肾脏对液体运输的调节。

The mechanism of ion transport and their modifications by several neurotransmitters will be studied with electrophysiological techniques in isolated perfused segments (S1, S2, S3) of rabbit proximal tubules. Experiments are designed 1) to determine the passive properties of apical and basolateral membranes and paracellular pathway by measuring a) transepithelial resistance, b) apparent ratio of apical to basolateral membrane resistance, and c) cell membrane potentials. These data will allow us to calculate the equivalent electrical resistances and electromotive forces of the cell membranes. Ionic substitutions will be used to determine the ionic diffusional permeability of the cell membranes. 2) To study the effects of norepinephrine, dopamine, acetylocholine and other substances which modify fluid reabsorption on the passive properties of the cell membranes. 3) To determine the steady-state intracellular activities of Na, K and C1, by using ion-sensitive microelectrodes to define uphill and downhill transport process and to ascertain whether passive ion transport at a given membrane can be electrodiffusional. If these experiments are successful, intracellular ion activity measurements will be applied to the study of the mechanism of action of neurotransmitters which modify fluid transport. These experiments should provide a better understanding of proximal tubular function and of the regulation of fluid transport by the kidney as a whole.