Adenosine Triphosphatase Localization in Amphibian Epidermis

Farquhar, Marilyn G.; Palade, George E.

doi:10.1083/jcb.30.2.359

Cited by 199 publications

(68 citation statements)

References 65 publications

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“…Cells are connected to each other through low resistance paths (Ussing & Windhager, 1964). The Na pumps are located at the cell-intercellular space boundary (Farquhar & Palade, 1966;Rotunno 128 ADH EFFECT ON Na INFLUX et al 1966). When Na from the outer bathing solution penetrates into the cells it follows mainly two routes: (1) some Na ions are actively extruded toward the interspace.…”

Section: Discussionmentioning

confidence: 99%

“…Although the results fit, in a general way, the scheme of the mechanism of ADH activity mentioned above, they indicate that the concept that it accelerates the pumping by increasing the Na-pool might not be true. This information is discussed with respect to current models of Na transport (Ussing, 1964;Farquhar & Palade, 1966;Biber, Chez & Curran, 1966; Cereijido & Rotunno, 1968).…”

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confidence: 99%

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The effect of antidiuretic hormone on Na movement across frog skin

Cereijido¹,

Rotunno²

1971

The Journal of Physiology

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SUMMARY1. The effect of antidiuretic hormone (ADH) on the movement and distribution of Na was studied. This was done using three different approaches: (a) the measurement of Na and 22Na in slices of epithelium of skins which were exposed to Ringer of varied composition containing 22Na, (b) the measurement of the influx of Na from the outer to the inner bathing solution with 22Na added to the outside, and (c) the use of a recently introduced technique which permits the direct evaluation of the flux from the outer solution -÷ epithelium, (JOT), i.e. the flux across the barrier which is generally regarded as the site of ADH activity.2. ADH increased the influx from the outer to the inner bathing solution of Na (50 %) not only when the concentration of Na on the outside was 115 mM (i.e. higher than in the epithelium) but even when the concentration was 1 mM (67 %).3. When the skin was bathed with 1mM-Na Ringer on the outside, ADH increased the unidirectional Na flux JOT by 56 % (Rana pipiens) and 71 % (Leptodactylus ocellatus). When the concentration was 115 mm a small increase (17 %) was observed in paired skins of R. pipiens. Under this condition no change was observed in L. ocellatus. 4. The amount of epithelial sodium which is labelled by 22Na added to the outside was taken to reflect the amount of Na involved in Na transport across the epithelium. Depending on whether the concentration of Na on the outside was high (115 mM) or low (1 mM), ADH produced an increase, or a decrease, of both the total Na content and the amount of 22Na exchanged.5. When the concentration of Na on the outside was low, ADH increased the total influx and JOT in spite of the fact that it lowers the total Na content and does not affect the exchangeable pool of Na. This observation is inconsistent with the view that the effect of ADH is due to the fact M. CEREIJIDO AND C. A. ROTUNNO that the increased permeability of the outer barrier allows more Na into the cell, and that the resulting increase of Na concentration in the cytoplasm accelerates the Na pumps at the inner side of the cells.6. It is concluded that ADH speeds up Na movements at the outward facing barrier, and that this exchange which facilitates the penetration of Na into a transporting compartment produces also a gain or a loss of Na in compartments not directly involved in Na transport across the epithelium. One compartment which is not involved in Na transport might be the cytoplasm of the epithelial cells.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

The effect of antidiuretic hormone on Na movement across frog skin

Cereijido¹,

Rotunno²

1971

The Journal of Physiology

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“…Cells from all epithelial layers are interconnected by intercellular junctions, forming a syncytium (Farquhar and Palade, 1964;Rick, D6rge, Arnim, and Thurau, 1978). The inner membrane of the S. granulosum and all membranes of the innermost layers contain Na-K ATPase (Farquhar and Palade, 1966;Mills, Ernst, and DiBona, 1977) and, presumably, the K channels that confer high K selectivity to the basolateral membrane. Na absorption involves an entry step through apical channels and an active extrusion from the cell by the Na-K ATPase in exchange for K uptake.…”

Section: Introductionmentioning

confidence: 99%

Whole-cell and single channel K+ and Cl- currents in epithelial cells of frog skin.

1991

The Journal of General Physiology

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A B S T R A C T Whole-cell and single channel currents were studied in cells from frog (R. pipiens and R. catesbiana) skin epithelium, isolated by collagenase and trypsin treatment, and kept in primary cultures up to three days. Whole-cell currents did not exhibit any significant time-dependent kinetics under any ionic conditions used. With an external K gluconate Ringer solution the currents showed slight inward rectification with a reversal potential near zero and an average conductance of 5 nS at reversal. Ionic substitution of the external medium showed that most of the cell conductance was due to K and that very little, if any, Na conductance was present. This confirmed that most cells originate from inner epithelial layers and contain membranes with basolateral properties. At voltages more positive than 20 mV outward currents were larger with K in the medium than with Na or N-methyl-Dglucamine. Such behavior is indicative of a multi-ion transport mechanism. Wholecell K current was inhibited by external Ba and quinidine. Blockade by Ba was strongly voltage dependent, while that by quinidine was not. In the presence of high external CI, a component of outward current that was inhibited by the anion channel blocker diphenylamine-2-carboxylate (DPC) appeared in 70% of the cells. This component was strongly outwardly rectifying and reversed at a potential expected for a C1 current. At the single channel level the event most frequently observed in the cell-attached configuration was a K channel with the following characteristics: inward-rectifying I-V relation with a conductance (with 112.

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“…In the first model proposed by KoefoedJohnsen and Ussing (1) it was localized on the outer aspect of the stratum germinativum. Later results suggested that its localization should be moved outwards (14,15). Kidder, Cereijido, and Curran (16) postulated that the sodium barrier was located near or at the anatomical outer surface of the skin; this would explain the time evolution of potentials when sodium outside was increased.…”

Section: Site Of Responsementioning

confidence: 99%

Induced Pacemaker Activity on Toad Skin

Bueno

Corchs

1968

The Journal of General Physiology

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The electrical transients produced on the isolated abdominal skin obtained from Bufo arenarurn Hensel, under the influence of inward current pulses of constant intensity have been studied. When both faces of the skin are bathed with Ringer's solution, short pulses of inward current give rise to transient variations of the potential difference between both faces of the skin with "all-or-nothing" characteristics (action potentials, A.P). When the outer face is bathed with a modified Ringer solution with low sodium content (2.4 mu), the transients are longer and they are only evident when the pulse is several hundred milliseconds long. With even longer pulses (several seconds) a repetitive activity can be elicited, with the electrical characteristics of a "pacemaker" activity. In all these "excitability" phenomena Na + may be replaced by Li + in the outer solution. The logarithm of the duration of AP's is inversely related to the logarithm of the increase in concentration of Na + or Li + in the solution bathing the external face of the skin. The duration of AP's is increased when the Ca ++ concentration in the outer solution is raised. This effect is more evident with low sodium concentration on the outside. The evolution of the slope conductance during repetitive activity has been determined. The site and mechanisms of the "excitable" behavior of the skin and the induced repetitive activity are discussed. Under the experimental conditions employed the behavior of the skin is compared with that of normally excitable plasma membranes. I N T R O D U C T I O NDuring the last decade a number of studies have been carried out to elucidate the mechanism of active sodium transport in isolated surviving frog skin. The information obtained gives insight on ion transporting properties of other epithelial membranes. Koefoed-Johnsen and Ussing (1) demonstrated that the electrical potential through the skin is dependent upon both the concentrations of sodium bathing the outer surface and of potassium bathing the inner surface. T h e y proposed a model based on their results to explain the electrical behavior of the skin. This model assumes the existence of two major diffusion barriers: (a) an outward facing barrier impermeable to all cations except Na+ and Li +, and (b) an inward facing barrier permeable to K+ and

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Adenosine Triphosphatase Localization in Amphibian Epidermis

Cited by 199 publications

References 65 publications

The effect of antidiuretic hormone on Na movement across frog skin

The effect of antidiuretic hormone on Na movement across frog skin

Whole-cell and single channel K+ and Cl- currents in epithelial cells of frog skin.

Induced Pacemaker Activity on Toad Skin

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