Summary
Transepithelial Li+ influx was studied in the isolated epithelium from abdominal skin ofRana catesbeiana. With Na+-Ringer's as inside medium and Li+-Ringer's as outside medium, the Li+ influx across the epithelium was 15.6 μA/cm2. This influx was considerably reduced by removal of either Na+ or K+ from the inside bath or by the addition of ouabain or amiloride. Epithelial K+ or Na+ concentration was respectively lower in epithelia bathed in K+-free Ringer's or Na+-free Ringer's. In conditions of negligible Na+ transport, a 20mm Li+ gradient (out→in) produced across the short-circuited epithelium a Li+ influx of 11.8 μA/cm2 and a mean short-circuit current of 10.2 μA/cm2. The same Li+ gradient in the opposite direction produced a Li+ outflux of only 1.9 μA/cm2. With equal Li+ concentration (10.3 and 20.6mm) on both sides of the epithelium, plus Na+ in the inside solution only, a stable Li+-dependent short-circuit current was observed. Net Li+ movement (out→in) was also indirectly determined in the presence of an opposing Li+ gradient. Although Li+ does not substitute for Na+ as an activator of the (Na++K+)-ATPase from frog skin epithelium, Li+ influx appears to be related to Na+−K+ pump activity. It is proposed that the permeability of the “outer barrier” to Na+ and Li+ is regulated by the electrical gradient produced by electrogenic Na+−K+ pumps located in the membrane of the deeper epithelial cells.
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References
Aceves, J., Erlij, D. 1971. Sodium transport across the isolated epithelium of the frog skin.J. Physiol. 212:195
Biber, T.U.L., Chez, R.A., Curran, P.E. 1966. Na transport across frog skin at low external Na concentrations.J. Gen. Physiol. 49:1161
Biber, T.U.L., Cruz, L.J. 1973. Effect of antidiuretic hormone on sodium uptake across outer surface of frog skin.Amer. J. Physiol. 225:912
Biber, T.U.L., Curran, P.F. 1970. Direct measurement of uptake of sodium at the outer surface of the frog skin.J. Gen. Physiol. 56:83
Bonting, S.L., Canady, M.R. 1964. Na−K activated adenosine triphosphatase and sodium transport in toad bladder.Amer. J. Physiol. 207:1005
Bonting, S.L., Caravaggio, L.L., Hawkins, N.M. 1962. Studies on sodium-potassium-activated adenosinetriphosphatase. IV. Correlation with cation transport sensitive to cardiac glycosides.Arch. Biochem. Biophys. 98:413
Candia, O.A. 1970. The hyperpolarizing region of the current-voltage curve in frog skin.Biophys. J. 10:323
Candia, O.A. 1972. Ouabain and sodium effects on chloride fluxes across the isolated bullfrog cornea.Amer. J. Physiol. 223:1053
Candia, O.A., Chiarandini, D.J. 1973. Transport of lithium and rectification by frog skin.Biochim. Biophys. Acta 307:578
Candia, O.A., Reinach, P. 1975. The Na pool and Na fluxes across inner and outer barriers of frog skin epithelium.Biophys. J. 15:228a (#2 Abstract)
Candia, O.A., Zadunaisky, J.A. 1972. Potassium flux and sodium transport in the isolated frog skin.Biochim. Biophys. Acta 225:517
Cereijido, M., Herrera, F.C., Flanigan, W.J., Curran, P.F. 1964. The influence of Na concentration on Na transport across frog skin.J. Gen. Physiol. 47:879
Erlij, D., Smith, M.W. 1973. Sodium uptake by frog skin and its modification by inhibitors of transepithelial sodium transport.J. Physiol. 228:221
Finkelstein, A. 1961. Lithium-induced oscillations of potential and resistance in isolated frog skin.J. Gen. Physiol. 44:1165
Kawada, J., Taylor, R.E., Jr., Barker, S.B. 1969. Measurement of Na−K-ATPase in the separated epidermis ofRana catesbeiana frogs and tadpoles.Comp. Biochem. Physiol. 30:965
Koefoed-Johnsen, V. 1957. The effect ofg-Strophanthin (ouabain) on the active transport of sodium through the isolated frog skin.Acta Physiol. Scand. 42 (Suppl. 145):87
Koefoed-Johnsen, V., Ussing, H.H. 1958. The nature of the frog skin potential.Acta Physiol. Scand. 42:298
Leblanc, G. 1972. The mechanism of lithium accumulation in the isolated frog skin epithelium.Pflugers Arch. 337:1
Moreno, J.H., Reisin, I.L., Rodriquez Boulan, E., Rotunno, C.A., Cereijido, M. 1973. Barriers to sodium movement across frog skin.J. Membrane Biol. 11:99
Rabito, C.A., Rodriquez Boulan, E., Cereijido, M. 1973. Effect of the composition of the inner bathing solution on transport properties of the frog skin.Biochim. Biophys. Acta 311:630
Rajerison, R.M., Montegut, M., Jard, S., Morel, F. 1972. The isolated frog skin epithelium: Permeability characteristics and responsiveness to oxytocin, cyclic AMP and theophylline.Pflugers Arch. 332:302
Rotunno, C.A., Vilallonga, F.A., Fernandez, M., Cereijido, J. 1970. The penetration of sodium into the epithelium of the frog skin.J. Gen. Physiol. 55:716
Rotunno, C.A., Zylber, E.A., Cereijido, M. 1973. Ion and water balance in the epithelium of the abdominal skin of the frogLeptodactylus ocellatus.J. Membrane Biol. 13:217
Siegel, G.J., Tormay, A., Candia, O.A. 1975. Microsomal sodium-potassium-activated adenosinetriphosphatase from frog skin epithelium: Cation activation and some effects of inhibitors.Biochim. Biophys. Acta 389:557
Ussing, H. 1965. Transport of electrolytes and water across epithelia.Harvey Lect. 59:1
Zerahn, K. 1969. Nature and localization of the sodium pool during active transport in the isolated frog skin.Acta Physiol. Scand. 77:272
Zylber, E.A., Rotunno, C.A., Cereijido, M. 1973. Ion and water balance in isolated epithelial cells of the abdominal skin of the frogLeptodactylus ocellatus.J. Membrane Biol. 13:199
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Reinach, P.S., Candia, O.A. & Siegel, G.J. Lithium transport across isolated frog skin epithelium. J. Membrain Biol. 25, 75–92 (1975). https://doi.org/10.1007/BF01868569
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DOI: https://doi.org/10.1007/BF01868569