Abstract
1. The electrical properties of the proximal tubular cells were studied in the newt kidney by using microelectrode techniques.
2. The surface membrane of the tubular cells behaved like a simple resistor when a minute current was applied intracellularly. The changes in the transmembrane potential was linearly proportional to the strength of applied current and there was neither the rectification nor the self-generative response within. a wide range of current strength.
3. The potential change caused by the intracellular application of current spread over considerable distances along the longitudinal axis of the tubule. The tubular wall, thus, behaved like a core conductor.
4. Application of the simple core conductor theory to the model of the tubular wall gave the values of 400μ for the space constant, 3.1×105Ωfor the effective resistance, 836Ωcm2 for the specific resistance of the surface membrane and 625Ωcm for the specific resistance of the core (cytoplasm including intercellular membranes).
5. A comparison of the surface membrane resistance to the transtubular resistance suggests that there are significant extracellular shunt paths for electrolytes within the tubular wall. The leaky nature of the proximal segment was ascribed to the presence of such shunt paths.
