Exchange diffusion, electrodiffusion and rectification in the chloride transport pathway of frog skin

Kristensen, Poul

doi:10.1007/bf01870321

Cited by 55 publications

(28 citation statements)

References 21 publications

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“…2). This is somewhat surprising, given previous data on the trans dependence of Cl flux in frog skin (32). Nonetheless, the overall basolateral Km of 2.…”

Section: Discussionmentioning

confidence: 69%

Cyclic adenosine monophosphate-stimulated anion transport in rabbit cortical collecting duct. Kinetics, stoichiometry, and conductive pathways.

Schuster¹

1986

J. Clin. Invest.

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Cyclic AMP stimulates HCO3 secretion and Cl self-exchange in rabbit cortical collecting tubule. We found that varying peritubular ICII changed the Cl self-exchange rate with saturation kinetics (K., 34 mM). HCO3 secretion also showed saturation kinetics as a function of mean luminal jCI] (K., 4-11 mM). Both Cl self-exchange and CI-HC03 exchange thus appear to be carrier-mediated. Addition/removal of basolateral HCO3 qualitatively changed Cl and HCO3 transport as expected for CI-HCO3 exchange, but quantitatively changed Cl absorption more than HCO3 secretion. The diffusive Cl permeability and the transepithelial conductance in the presence of HCO3/CO2 and cAMP were higher than in their absence suggesting that HCO3/CO2 and cAMP together increase a conductive Cl pathway parallel to a 1:1 CI-HCO3 exchanger. Thus, cAMP not only stimulates the overall process of anion exchange (probably by increasing an electroneutral exchanger and/or a series Cl conductance), but also stimulates a Cl conductance parallel to the exchange process.

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“…2). This is somewhat surprising, given previous data on the trans dependence of Cl flux in frog skin (32). Nonetheless, the overall basolateral Km of 2.…”

Section: Discussionmentioning

confidence: 69%

Cyclic adenosine monophosphate-stimulated anion transport in rabbit cortical collecting duct. Kinetics, stoichiometry, and conductive pathways.

Schuster¹

1986

J. Clin. Invest.

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“…Whereas considerable voltage-activated G Cl was generally observed in skins from B. viridis, skins from R. esculenta were either lacking notable Cl -conductance or contained spontaneously high G Cl at short circuit, which was in most cases insensitive to voltage or developed over extended periods of time (5-10 min). Other species of frogs display the same variability [10]. Nevertheless, if G Cl is present, differences in response patterns are no more pronounced among species than between the two genera.…”

Section: Discussionmentioning

confidence: 83%

Effects of Aminoperimidine on Electrolyte Transport across Amphibian Skin

Nagel¹,

Shalitin

Katz

1998

Cell Physiol Biochem

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The effect of aminoperimidine (AP) on transepithelial Na⁺ transport and Cl^– conductance (G^Cl) of isolated amphibian skin (Bufo viridis and Rana esculenta) was analyzed using transepithelial and intracellular electrophysiological techniques. AP, applied at concentrations between 30 and 100 µM from the mucosal side, stimulated Na⁺ transport rapidly and reversibly by more than 30% of the control value due to an increase in apical membrane Na⁺ permeability. Influence of AP on basolateral membrane conductance and effective driving force for Na⁺ were negligible. Voltage-activated G^Cl of toad skin, but not the resting, deactivated conductance, as well as spontaneously high G^Cl in frog skin was rapidly inhibited by AP in a concentration-dependent manner. The half-maximal inhibitory concentration of 20 µM is the highest hithero reported inhibitory power for G^Cl in amphibian skin. The effect of AP on G^Cl was slowly and incompletely reversible even after brief exposure to the agent. Serosal application of AP had similar, albeit delayed effects on both Na⁺ and Cl^– transport. AP did not interfere with the Cl^– pathway after it was opened by 100–300 µM CPT-cAMP, a membrane-permeable, nonhydrolyzed analogue of cAMP. Inhibition of the voltage-activated G^Cl by AP was attenuated or missing when AP was applied during voltage perturbation to serosa-positive potentials. Since AP is positively charged at physiological pH, it suggests that the affected site is located inside the Cl^– pathway at a certain distance from the external surface. AP affects then the Na⁺ and Cl^– transport pathways independent of each other. The nature of chemical interference with AP, which is responsible for the influence on the transport of Na⁺ and Cl^–, remains to be elucidated.

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“…On the other hand, Narvarte and Finn (1980) claimed that the apical membrane of the toad bladder (Mexican origin) has a finite CI conductance, raising the possibility that C1 transport may be in part transcellular. In amphibian skin, a voltage-dependent apical C1 conductance has been observed (Larsen & Kristensen, 1978;Kristensen, 1983). This conductance may reside in mitochondria-rich rather than granular cells (Vofite & Meier, 1978;Kristensen, 1981).…”

Section: Introductionmentioning

confidence: 97%

Single-channel recordings of apical membrane chloride conductance in A6 epithelial cells

Nelson¹,

Tang²,

Palmer

1984

J. Membrain Biol.

167

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The apical membrane of epithelial cells from the A6 cell line grown on impermeable substrata was studied using the patch-clamp technique. We defined the apical membrane as that membrane in contact with the growth medium. In about 50% of the patches, channels with single-unit conductances of 360 +/- 45 pS in symmetrical 105 mM NaCl solutions, and characteristic voltage-dependent inactivation were observed. Using excised membrane patches and varying the ionic composition of the bathing medium, we determined that the channels were anion selective, with a permeability ratio for Cl- over Na+ of about 9:1, calculated from the reversal potential using the constant-field equation. The channel was most active at membrane potentials between +/- 20 mV and inactivated, usually within a few seconds, at higher potentials of either polarity. Reactivation from this inactivation was slow, sometimes requiring minutes. In addition to its fully open state, the channel could also enter a flickering state, which appeared to involve rapid transitions to one or more submaximal conductance levels. The channel was inhibited by the disulfonic stilbene SITS in a manner characteristic of reversible open-channel blockers.

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Exchange diffusion, electrodiffusion and rectification in the chloride transport pathway of frog skin

Cited by 55 publications

References 21 publications

Cyclic adenosine monophosphate-stimulated anion transport in rabbit cortical collecting duct. Kinetics, stoichiometry, and conductive pathways.

Cyclic adenosine monophosphate-stimulated anion transport in rabbit cortical collecting duct. Kinetics, stoichiometry, and conductive pathways.

Effects of Aminoperimidine on Electrolyte Transport across Amphibian Skin

Single-channel recordings of apical membrane chloride conductance in A6 epithelial cells

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