The Influence of Na Concentration on Na Transport across Frog Skin

Cereijido, Marcelino; Herrera, Flor; Flanigan, William J.; Curran, Peter F.

doi:10.1085/jgp.47.5.879

Cited by 126 publications

(88 citation statements)

References 10 publications

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“…Kirschner (9) found that shortcircuit current across frog skin rose by increasing sodium concentration, reached a maximum at about 35 meq/liter of external Na and then decreased as the concentration was raised further. Cereijido et al (1) interpreted the saturation of the rate of sodium transport in Rana pipiens with increasing external Na concentration as due, in part, to changes in the permeability of the outer membrane rather than to saturation of the transporting system ("pump") itself. Cirne and Malnic (2) observed that short-circuit current in the toad skin of Bufo paracnemis and Bufo ictericus could be fitted in the range of 5-50 meq/liter external Na concentration by Michaelis-Menten kinetics.…”

Section: Discussionmentioning

confidence: 99%

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Nonequilibrium Thermodynamic Analysis of the Coupling between Active Sodium Transport and Oxygen Consumption

Danisi

Vieira

1974

The Journal of General Physiology

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AB STRACT Sodium transport and oxygen consumption have been simultaneously studied in the short-circuited toad skin. A constant stoichiometric ratio was observed in each skin under control condition (NaCI-Ringer's solution bathing both sides of the skin) and after block of sodium transport by ouabain. During alterations of sodium transport by removal and addition of K to the internal solution the stoichiometric ratio is constant although having a value higher than that observed in other untreated skins. The coupling between active sodium transport and oxygen consumption was studied after a theoretical nonequilibrium thermodynamic model. Studies were made of the influence of Na chemical potential difference across the skin on the rates of Na transport and oxygen consumption. A linear relationship was observed between the rates of Na transport and oxygen consumption and the Na chemical potential difference. Assuming the Onsager relationship to be valid, the three phenomenological coefficients which describe the system were evaluated. Transient increases in the rate of sodium transport and oxygen consumption were observed after a transitory block of sodium transport by removal of Na from the external solution. Cyanide blocks completely the rate of oxygen consumption in less than 2 min and the short-circuit current measured after that time decays exponentially with time, suggesting a depletion of ATP from a single compartment.

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Section: Discussionmentioning

confidence: 99%

“…Initial point of each period is indicated by letters (A, before block of Na transport and B, after block of Na transport). 1 (0.60 < P < 0.70, n = 10, paired t test). LNarA(before) = 102.7…”

Section: Active Sodium Transport and Oxygen Consumption As A Functionmentioning

confidence: 97%

Nonequilibrium Thermodynamic Analysis of the Coupling between Active Sodium Transport and Oxygen Consumption

Danisi

Vieira

1974

The Journal of General Physiology

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“…It seems more reasonable to postulate a carrier mechanism at the outer surface, which may well saturate at a fairly low level of concentration of Na in the outer bathing medium. Cereijido et al (1964) discuss such mechanisms in relation to their provocative and precise measurements on the effects of Na concentration on Na transport across isolated bits of frog skin. …”

Section: Discussionmentioning

confidence: 99%

The Sodium and Potassium Exchange between Intact Frogs and Their Environment

1966

The Journal of General Physiology

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Intact living frogs (Rana pipiens) were partially immersed in dilute salt solution labeled with K 42 or Na 24 or, alternatively, injected with Ringer's fluid containing the appropriate isotope and then partially immersed in unlabeled dilute salt. Before isotopic equilibrium, the animals were sacrificed and specific activities of K 42 and Na 24 were determined for medium, skin, plasma, and other tissues. With Na 24 , entering from the medium or escaping to the medium, specific activities of the skin approach that of the plasma. For K 42 , entering from the medium, the specific activity exceeds that of the plasma. The results are interpreted as indicating that the exchange rate for Na is greater plasma to skin than medium to skin, with the reverse situation for K. Values are given for average Na, K, and CI contents of the various organ systems.Intact frogs sitting in pond water or dilute saline solutions will transfer Na and CI from the environment to the body against the considerable chemical gradient (seeKrogh, 1939). K and Ca, on the other hand, are not known to be transferred on a net basis, although studies on isotope exchange have not been reported extensively. The ability of the isolated frog skin to move ions and water has been clearly demonstrated over a period of several decades. Such studies, usually with high salt (Ringer's fluid or equivalent osmotic concentration) on both sides of the skin, may or may not have relevance to the physiological functioning of the skin in situ with the animal in a normal environment. For example, the intact skin is apparently able to regulate water inflow very precisely from pond water to near Ringer's fluid strength, while the denervated skin seems to behave as a simple osmotic membrane (see Adolph, 1933) so far as adjustments to osmotic changes are concerned.Penetration of ions both into and across the isolated skin bathed in physiological salt solutions generally appears to follow the rules stated by Ussing and his coworkers (see MacRobbie and Ussing, 1961):1. The outward facing boundary of the epithelium is permeable to Na and CI but impermeable to K and S0 4 .

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“…As explained above, the size of L. ocellatus does not permit the study of paired samples of skins from the same animal. 22Na uptake When 22Na was added to the outer bathing solution the influx of 22Na reached equilibrium in less than 20 min (Hoshiko & Ussing, 1960;Curran et al 1963;Cereijido, Herrera, Flanigan & Curran, 1964;Cereijido & Rotunno, 1967). It can be demonstrated that by the time the influx of 22Na equilibrates, the Na transporting compartment should have its 22Na-specific activity in a steady state (Solomon, 1960).…”

Section: Na Influxmentioning

confidence: 99%

“…Hence the number of counts per minute of 22Na in the epithelium divided by the specific activity of 22Na in the outer chamber can be taken as an estimate of the amount of Na in the transporting compartment, in particular if, as it is the case in the present paper, only comparative studies are intended. There is a relationship between the amount of Na in this compartment and the rate of Na pumping Cereijido et al 1964). It was suggested Crabbe & de Weer, 1965), that the increase in Na permeability of the outer barrier elicited by ADH, produces a rise in the concentration of Na in the transporting compartment, and that the Na pump located at the inner 126 ADH EFFECT ON Na INFLUX1 barrier reacts to this rise in concentration by pumping more Na toward the inside.…”

Section: Na Influxmentioning

confidence: 99%

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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The Influence of Na Concentration on Na Transport across Frog Skin

Cited by 126 publications

References 10 publications

Nonequilibrium Thermodynamic Analysis of the Coupling between Active Sodium Transport and Oxygen Consumption

Nonequilibrium Thermodynamic Analysis of the Coupling between Active Sodium Transport and Oxygen Consumption

The Sodium and Potassium Exchange between Intact Frogs and Their Environment

The effect of antidiuretic hormone on Na movement across frog skin

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