Sodium Flux in Necturus Proximal Tubule under Voltage Clamp

Sodium Flux in Necturus Proximal Tubule under Voltage Clamp

Na transport and electrical properties of Necturus renal proximal tubules were analyzed, in vivo, by a voltage clamp method which utilizes an axial electrode in the tubule lumen for passage of current and simultaneous determination of net fluid (or Na) flux by the split droplet method. When the average spontaneous transepithelial potential difference of -8 mv (lumen negative) was reduced to zer...

Kinetics of Na(+) transport in necturus proximal tubule

The dependence of proximal tubular sodium and fluid readsorption on the Na(+) concentration of the luminal and peritubular fluid was studied in the perfused necturus kidney. Fluid droplets, separated by oil from the tubular contents and identical in composition to the vascular perfusate, were introduced into proximal tubules, reaspirated, and analyzed for Na(+) and [(14)C]mannitol. In addition,...

Conductive properties of the proximal tubule in Necturus kidney

The electrical properties of the proximal tubule of the in vivo Necturus kidney were investigated by injecting current (as rectangular waves) into the lumen or into the epithelium of single tubules and by studying the resulting changes of transepithelial (VL) and/or cell membrane potential (VC) at various distances from the source. In some experiments paired measurements of VL and VC were perfo...

Osmotic Volume Flow in the Proximal Tubule of Necturus Kidney

Volume changes due to osmotic flow in the distal portion of proximal tubules of Necturi were measured by the split oil drop technique. In agreement with previous findings no volume flow was induced by NaCl concentrations close to 60 mM. The tubule wall was found to be permeable to plasma electrolytes, which have an apparent reflection coefficient of 0.69. The mean apparent hydraulic conductivit...

Micropuncture Study of Potassium Concentration in Proximal Tubule of Dog, Rat, and Necturus.