K+ transport in ‘Tight’ epithelial monolayers of MDCK cells
- 34 Downloads
Bidirectional transepithelial K+ flux measurements across ‘high-resistance’ epithelial monolayers of MDCK cells grown upon millipore filters show no significant net K+ flux.
Measurements of influx and efflux across the basal-lateral and apical cell membranes demonstrate that the apical membranes are effectively impermeable to K+.
K+ influx across the basal-lateral cell membranes consists of an ouabain-sensitive component, an ouabain-insensitive component, an ouabain-insensitive but furosemide-sensitive component, and an ouabain-and furosemide-insensitive component.
The action of furosemide upon K+ influx is independent of (Na+−K+)-pump inhibition. The furosemide-sensitive component is markedly dependent upon the medium K+, Na+ and Cl− content. Acetate and nitrate are ineffective substitutes for Cl−, whereas Br− is partially effective. Partial Cl− replacement by NO3 gives a roughly linear increase in the furosemide-sensitive component. Na+ replacement by choline abolishes the furosemide-sensitive component, whereas Li+ is a partially effective replacement. Partial Na+ replacement with choline gives an apparent affinity of ∼7mm Na, whereas variation of the external K+ content gives an affinity of the furosemide-sensitive component of 1.0mm.
Furosemide inhibition is of high affinity (K1/2=3 μm). Piretanide, ethacrynic acid, and phloretin inhibit the same component of passive K+ influx as furosemide; amiloride, 4,-aminopyridine, and 2,4,6-triaminopyrimidine partially so. SITS was ineffective.
Externally applied furosemide and Cl− replacement by NO 3 − inhibit K+ efflux across the basal-lateral membranes indicating that the furosemide-sensitive component consists primarily of K∶K exchange.
Key wordsK+ fluxes MDCK ouabain furosemide cultured epithelium Na++K++Cl− cotransport
Unable to display preview. Download preview PDF.
- Aiton, J.F., Chipperfield, A.R., Lamb, J.F., Ogden, P., Simmons, N.L. 1981. Passive K influx in cultured cells: Na and Cl dependence and furosemide sensitivity.J. Physiol. (London) 310:20P Google Scholar
- Aiton, J.F., Lamb, J.F. 1980. The effect of exogenous adenosine triphosphate on potassium movements in HeLa cells.Q. J. Expt. Physiol. 64:47–62Google Scholar
- Bakker-Grunwald, T. 1978. Effect of anions on potassium selfexchange in ascites tumour cells.Biochim. Biophys. Acta 513:292–295Google Scholar
- Bakker-Grunwald, T. 1981. Hormone-induced diuretic-sensitive potassium transport in turkey erythrocytes is anion dependent.Biochim. Biophys. Acta 641:289–293Google Scholar
- Barker, G., Simmons, N.L. 1981. Identification of two strains of cultured canine renal epithelial cells (MDCK cells) which display entirely different physiological properties.Q. J. Expt Physiol. 66:61–72Google Scholar
- Boardman, L., Huett, M., Lamb, J.F., Newton, J.P., Polson, J.M. 1974. Evidence for the genetic control of Na pump density in HeLa cells.J. Physiol. (London) 241:771–794Google Scholar
- Brown, C.D.A., Simmons, N.L. 1981. K+ transport in cultured renal cells of canine origin.J. Physiol. (London) 319:99P Google Scholar
- Burrows, R., Lamb, J.F. 1962. Sodium and potassium fluxes in cells cultured from chick embryo heart muscle.J. Physiol. (London) 162:510–531Google Scholar
- Cereijido, M., Robbins, E.S., Dolan, W.J., Rotunno, C.A. Sabatini, D.D. 1978. Polarised monolayers formed by epithelial cells on a permeable and translucent support.J. Cell Biol. 77:853–880Google Scholar
- Chipperfield, A.R. 1980. An effect of chloride on (Na+K) cotransport in human red cells.Nature (London) 286:281–282Google Scholar
- Chipperfield, A.R. 1981. Chloride dependence of frusemide and phloretin-sensitive passive sodium and potassium fluxes in human red cells.J. Physiol. (London) 312:435–444Google Scholar
- Civan, M.M. 1980. Potassium activities in epithelia.Fed. Proc. 39:2865–2870Google Scholar
- Cuthbert, A.W., Shum, W.K. 1974. Binding of amiloride to sodium channels in frog skin.Mol. Pharmacol. 10:880–891Google Scholar
- Dunham, P.B., Stewart, G.W., Ellory, J.C. 1980. Chloride-activated passive potassium transport in human erythrocytes.Proc. Natl. Acad. Sci. USA 77:1711–1715Google Scholar
- Fromter, E., Gebler, B. 1977. Electrical properties of amphibian urinary bladder epithelia.Pfluegers Arch. 371:99–108Google Scholar
- Geck, P., Heinz, E., Pietrzyk, C., Pfeiffer, B. 1978. The effect of furosemide on the ouabain-insensitive K+ and Cl− movement in Ehrlich cells.In: Cell Membrane Receptors for Drugs and Hormones R.W. Straub and I. Bolis, editors. pp. 301–307. Raven Press, New YorkGoogle Scholar
- Geck, P., Pietrzyk, C., Burckhardt, B.C., Pfeiffer, B., Heinz, E. 1980. Electrically silent cotransport of Na+, K+ and Cl− in Ehrlich cells.Biochim. Biophys. Acta 600:432–437Google Scholar
- Giebisch, G. 1979. Renal tubular control of potassium transport.Klin. Wochenschr 57:1001–1008Google Scholar
- Giebisch, G., Stanton, B. 1979. Potassium transport in the nephron.Annu. Rev. Physiol. 41:241–256Google Scholar
- Jorgenson, P.L. 1980. Sodium and potassium ion pump in kidney tubules.Physiol Rev. 60:864–917Google Scholar
- Koefoed-Johnsen, V., Ussing, H.H. 1958. The nature of the frog skin potential.Acta Physiol. Scand. 42:298–308Google Scholar
- Lamb, J.F., Ogden, P., Simmons, N.L. 1981. Autoradiographic localisation of3H-ouabain bound to cultured epithelial cell monolayers of MDCK cells.Biochim. Biophys. Acta 646:333–340Google Scholar
- Lewis, S.A., Eaton, C.D., Clausen, C., Diamond, J. 1977. Nystatin as a probe for investigating the electrical properties of a tight epithelium.J. Gen. Physiol. 70:427–440Google Scholar
- Naftalin, R.J., Simmons, N.L. 1979. The effects of theophylline and choleragen on sodium and chloride movements within isolated rabbit ileum.J. Physiol. (London) 290:331–350Google Scholar
- Nellans, H.N., Schultz, S.G. 1976. Relations among transepithelial sodium transport, potassium exchange, and cell volume in rabbit ileum.J. Gen. Physiol. 68:441–463Google Scholar
- Richardson, J.C.W., Scalera, V., Simmons, N.L. 1981. Identification of two strains of MDCK cells which resemble separate nephron tubule segments.Biochim. Biophys. Acta 673:26–36Google Scholar
- Rindler, N.J., McRoberts, J., Saier, M.H. 1980. Na+−K+ cotransport in dog kidney epithelial cells (MDCK).J. Supramol. Struct. 4:86Google Scholar
- Simmons, N.L. 1979. Ion transport in high-resistance dog-kidney cell monolayers, the effect of adenosine 5′ triphosphate.J. Physiol. (London) 290:28PGoogle Scholar
- Simmons, N.L. 1981a. Ion transport in ‘tight’ epithelial monolayers of MDCK cells.J. Membrane Biol. 59:105–114Google Scholar
- Simmons, N.L. 1981b. The action of ouabain upon chloride secretion in cultured MDCK epithelium.Biochim. Biophys. Acta 646:243–250Google Scholar
- Simmons, N.L., Naftalin, R.J. 1976. Bidirectional Na ion movements via the paracellular and transcellular routes across shortcircuited rabbit ileum.Biochim. Biophys. Acta 448:426–450Google Scholar
- Snedecor, G.W., Cochran, W.G. 1968. Statistical Methods. pp. 135–136. Iowa State University Press, AmesGoogle Scholar
- Wiley, J.S., Cooper, R.A. 1974. A furosemide-sensitive cotransport of sodium plus potassium in the human red cell.J. Clin. Invest. 53:745–755Google Scholar