Summary
This paper describes properties of86Rb fluxes through K channels in “luminal” membrane vesicles prepared from rabbit renal outer medulla. By measuring86Rb uptake against an opposing chemical gradient of K ions, using membranes loaded with KCl, a transient accumulation of isotope is observed, which is blocked by Ba ions. This is the behavior expected of a conductive Rb flux through a Ba-sensitive K channel. The86Rb accumulation is driven by an electrical diffusion potential as shown in experiments using either vesicles loaded with different anions, or an outwardly directed Li gradient with a Li ionophore. The vesicles containing the channel show a cation selectivity with the order Rb > K > Cs > Li > Na > choline. The Ba-sensitive Rb flux is dependent on Ca within the vesicles, with a very high affinity estimated asK 0.5 10 to 100nm. The vesicles appear to be right-side-out. The Ba-sensitive86Rb uptake is also inhibited by quinineK 0.5 30 μm but is insensitive to tetraethyl ammonium ions and apamin. These isotope flux experiments complement electrophysiological experiments in providing independent evidence for the existence of K channels in the luminal surface of cells of this ascending limb of the loop of Henle. The very high Ca affinity suggests that cytoplasmic Ca could play an important role in regulation of transepithelial salt flux in this region of the nephron.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Andreoli, T.E., Schafer, A.J. 1976. Mass transport across cell membranes: The effects of antidiuretic hormone on water and solute flow in epithelia.Annu. Rev. Physiol. 38:183–223
Bradford, M.M. 1976. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding.Anal. Biochem. 72:248–254
Brown, C.D.A., Simmons, N.L. 1982. K+ transport in “tight” epithelial monolayers of MDCK cells. Evidence for a calcium-activated K+ channel.Biochim. Biophys. Acta 690:95–105
Burgess, G.M., Claret, M., Jenkinson, D.H. 1981. Effects of quinine and apamin on the calcium-dependent potassium permeability of mammalian hepatocytes and red cells.J. Physiol. (London) 317:67–90
Burnham, C., Karlish, S.J.D., Jorgensen, P.L. 1985. Identification and reconstitution of a Na+/K+/Cl− cotransporter and K+ channel from luminal membranes of renal red outer medulla.Biochim. Biophys. Acta 821:461–469
Eaton, D.C., Brodwick, M.S. 1980. Effects of barium on the potassium conductance of squid axon.J. Gen. Physiol. 75:727–750
Forbush, B., III 1982. Characterization of right-side-out membrane vesicles rich in (Na,K)ATPase and isolated from dog kidney outer modulla.J. Biol. Chem. 257:12678–12684
Forset, M., Schmid-Antomarchi, H., Hugues, M., Romey, G., Lazdunski, M. 1984. The presence in pig brain of an endogenous equivalent of apamin the bee venom peptide that specifically blocks Ca2+-dependent K+ channels.Proc. Natl. Acad. Sci. USA 81:7228–7232
Garty, H., Karlish, S.J.D. 1986. Measurement of ion channel mediated fluxes in membrane vesicles. Selective amplification of isotope uptake by electrical diffusion potentials.Methods Enzymol. (in press)
Garty, H., Rudy, B., Karlish, S.J.D. 1983. A simple and sensitive procedure for measuring isotope fluxes through ion-specific channels in heterogenous population of membrane vesicles.J. Biol. Chem. 258:13094–13099
Greger, R. 1985. Ion transport mechanism in thick ascending limb of Henle's loop of mammalian nephron.Physiol. Rev. 65:760–797
Greger, R., Schlatter, E. 1983a. Properties of the lumen membrane of cortical thick ascending limb of henle's loop of rabbit kidney.Pfluegers Arch. 396:315–324
Greger, R., Schlatter, E. 1983b. Properties of the basolateral membrane of the cortical thick ascending limb of henle's loop of rabbit kidney. A model for secondary active chloride transport.Pfluegers Arch. 396:325–334
Greger, R., Schlatter, E., Lang, F. 1983. Evidence for electroneutral sodium chloride cotransport in cortical thick ascending limb of Henle's loop of rabbit kidney.Pfluegers Arch. 396:308–314
Hebert, S.C., Andreoli, T.E. 1984a. Effects of antidiuretic hormone on cellular conductive pathways in mouse medullary thick ascending limbs of Henle. II. Determinants of the ADH-mediated increases in transepithelial voltage and in net Cl− absorption.J. Membrane Biol. 80:221–233
Hebert, S., Andreoli, T.E. 1984b. Control of NaCl transport in the thick ascending limb.Am. J. Physiol. 246:F745-F756
Hebert, S.C., Culpepper, R.M., Andreoli, T.E. 1981. NaCl transport in mouse medullary thick ascending limbs. I. Functional nephron heterogeneity and ADH-stimulated NaCl cotransport.Am. J. Physiol. 241:F412-F431
Hebert, S.C., Friedman, P.A., Andreoli, T.E. 1984. Effects of antidiuretic hormone on cellular conductive pathways in mouse medullary thick ascending limbs of Henle: I. ADH increases transcellular conductance pathways.J. Membrane Biol. 80:201–219
Jorgensen, P.L. 1974. Purification and characterization of (Na+ +K+)-ATPase. III. Purification from the outer medulla of mammalian kidney after selective removal of membrane components by SDS.Biochim. Biophys. Acta 356:36–52
Latorre, R., Miller C 1983. Conduction and selectivity in potassium channels.J. Membrane Biol. 71:11–30
Lew, V.L., Ferreira, H.G. 1978. Calcium transport and the properties of a calcium-activated potassium channel in red cell membranes.Curr. Top. Memb. Transp. 10:217–279
Margalit, R., Shanzer, A. 1982. New Li+-selective ionophores with the potential ability to mediate Li+-transport in vivo. Ionic selectivity and relative potencies, studied in model membranes.Pfluegers Arch. 395:87–92
Marty, A. 1981. Ca-dependent K channels with large unitary conductance in chromaffin cell membranes.Nature (London) 291:497–500
Pershadsingh, H.A., McDonald, J.M. 1980. A high affinity calcium-stimulated magnesium dependent adenosine triphosphatase in rat adipocyte plasma membranes.J. Biol. Chem. 255:4087–4093
Petersen, O.H., Maruyama, Y. 1984. Calcium-activated potassium channels and their role in secretion.Nature (London) 307:693–696
Pfeiffer, D.R., Taylor, R.W., Lardy, H.A. 1978. Ionophore A23187: Cation binding and transport properties.Ann. N.Y. Acad. Sci. 307:402–423
Romey, G., Lazdunski, M. 1984. The co-existence in rat muscle cells of two distinct classes of Ca2+-dependent K+-channels with different pharmacological properties and different physiological functions.Biochim. Biophys. Res. Commun. 118:669–674
Schwartz, W., Passow, H. 1983. Ca2+-activated K+ channels in erythrocytes and excitable cells.Annu. Rev. Physiol. 45:359–374
Shanzer, A., Korenstein, R., Samuel, D. 1983. Lipophilic lithium ion carriers.J. Am. Chem. Soc. 105:3815–3818
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Burnham, C., Braw, R. & Karlish, S.J.D. A Ca-dependent K channel in “luminal” membranes from the renal outer medulla. J. Membrain Biol. 93, 177–186 (1986). https://doi.org/10.1007/BF01870809
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01870809