Cl^- transport in basolateral renal medullary vesicles: I. Cl^- transport in intact vesicles

This paper provides the results of studies which characterized conductive³⁶Cl^- flux in basolaterally enriched membrane vesicles prepared from rabbit renal outer medulla. Conductive³⁶Cl^- uptake was studied under two different experimental conditions. In the first,³⁶Cl^- flux was driven by an inside positive voltage created with oppositely directed Cl^- and gluconate gradients. In the second, an inwardly direct K⁺ gradient was used to drive³⁶Cl^- uptake. By these two methods, voltage-sensitive³⁶Cl^- uptake was shown to comprise about 45 and 65%, respectively, of the initial rates of total³⁶Cl^- flux. Separate paired studies demonstrated that the conductive³⁶Cl^- uptake was inhibited by the Cl^- channel blocker diphenylamine-2-carboxylate (DPC) with an IC₅₀ for DPC of 154 μm. The voltagedependent³⁶Cl^- uptake had an activation energy of 6.4 kcal/mole. This³⁶Cl^- conductance had an anion selectivity sequence of I^->Cl^-≧NO₃^-≫gluconate.