Cl⁻ transport in basolateral renal medullary vesicles: I. Cl⁻ transport in intact vesicles

Summary

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⁻≧NO ⁻₃ ≫gluconate.