Chloride balance in Rana pipiens

Alvarado, RH; Poole, AM; Mullen, TL

doi:10.1152/ajplegacy.1975.229.3.861

Cited by 20 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…J13 sodium from dilute solution such as occur in the animal's habitat. A high affinity component is also found in chloride transport from dilute solutions, its Ko.s being significantly different from that of the sodium transport mechanism and comparable with the in vivo and in vitro kinetic parameters reported by Alvarado et al for chloride transport from diluted solutions (Alvarado & Dietz, 1970;Alvarado, Dietz & Mullen, 1975;Alvarado, Poole & Mullen, 1975). By their level of saturation and their affinity this system may be identified with the physiological transport mechanism Cl~dHCO3int which is independent of the presence of sodium (Garcia-Romeu et al, 1969;Alvarado & Dietz, 1970;Garcia-Romeu & Ehrenfeld, 1975a-b;Ehrenfe!d & Garcia-Romeu, 1978).…”

Section: Evidence For Two Sodium and Chloride Transport Componentssupporting

confidence: 80%

Kinetics of ionic transport across frog skin: Two concentration-dependent processes

Ehrenfeld¹,

Garcia-Romeu²

1980

J. Membrain Biol.

View full text Add to dashboard Cite

Sodium and chloride influxes across the nonshort-circuited isolated skin of Rana esculenta were measured at widely varying external ionic concentrations. The curve describing sodium transport has two Michaelis-Menten components linked at an inflection point occurring at an external sodium concentration of about 7 meq. Chloride transport can also be represented by two saturating components. A possible explanation of these kinetics is discussed. At sodium concentrations lower than 4 meq it is possible to define a component of the sodium transport mechanism as having a high affinity for sodium and which is independent of the nature of the external anion. A high affinity for chloride of the chloride transport system functioning at low external concentrations is also found but is significantly different from that of sodium. These systems show the physiological characteristics of the countertransports (Na est(+)/H int(+); Cl ext(-)/HCO 3int(-)) functioning at low external concentrations. At external concentrations higher than 4 meq a low affinity transporting system in which chloride and sodium are linked superimpose on the high affinity compoents. The physiological significance of these results is discussed.

show abstract

Section: Evidence For Two Sodium and Chloride Transport Componentssupporting

confidence: 80%

Kinetics of ionic transport across frog skin: Two concentration-dependent processes

Ehrenfeld¹,

Garcia-Romeu²

1980

J. Membrain Biol.

View full text Add to dashboard Cite

show abstract

“…The passive diffusion of C1 down its concentration gradient would only make the discrepancy larger. However, it seems possible that this difference represents net inward movement of C1 as recently demonstrated in isolated frog skin (Alvarado, Dietz & Mullen, 1975 ;Alvarado, Poole & Mullen, 1975), although it might be due to the variability in the different measurements.…”

Section: Relationship Between Io and J~l~ Changes In Electrical Propmentioning

confidence: 90%

“…These alterations are probably due to the shunting effect of increased external C1. Not only should there be a direct increase in conductance because of high C1 concentration, but it has also been shown that high external C1 concentrations cause large increases in the permeability of the skin to C1, either because of the opening of paracellular shunts (Alvarado, Dietz & Mullen, 1975;Atvarado, Poole & Mullen, 1975;Mandel & Curren, I972) or the activation of an exchange diffusion system (Alvarado, Dietz & Mullen, 1975;Alvarado, Poole & Mullen, 1975;Braus, Kristensen & Larsen, 1976).…”

Section: Relationship Between Io and J~l~ Changes In Electrical Propmentioning

confidence: 99%

Effect of external cation and anion substitutions on sodium transport in isolated frog skin

Biber

Mullen

1980

J. Membrain Biol.

View full text Add to dashboard Cite

Effects of changes in external ionic strength, external cation and/or anion substitution on transepithelial influx and efflux of sodium, short-circuit current and on transepithelial potential difference and resistance were studied in isolated frog skin. Active transport of Na was found to be highly dependent on both anionic and cationic composition of external medium. Relative abilities of external monovalent cations to inhibit active Na transport were H greater than Li greater than K greater than Rb greater than Cs greater than choline. Relative abilities of external monovalent anions to stimulate active Na transport were I greater than Br greater than Cl. Sequences of anion interaction and of resistance changes suggest that anionic stimulation of Na transport is not due to electrical coupling across outer cell membrane. The ability of different anions and cations to alter Na transport suggests that externally located charged groups act as important barriers or filters to ion movement. In addition, the experiments suggest that an increase in ionic strength of external medium has an effect on active transport of Na, a finding that indicates interference of surface charges with Na entry. Directional changes in efflux of Na due to changes in ionic composition of external medium usually paralleled changes in active Na transport. It is possible that the observed relationship between influx and efflux of Na is the result of common pathways and of interaction of the active transport system with Na efflux.

show abstract

“…Under these conditions there is some doubt whether an adequate electrochemical gradient for sodium entry could exist across the apical membrane, and certainly transepithelial electrical gradients are too small to account for the paracellular uptake of chloride from the medium by purely passive means (Alvarado et al 1975). Furthermore, as originally shown by Krogh (1939), in the intact animal the uptake of sodium and of chloride from a dilute medium can occur independently of each other, which is not possible in the in vitro model described earlier, in which the transepithelial transport of chloride is electrically coupled to that of sodium.…”

Section: Sodium and Chloride Uptakementioning

confidence: 99%

Overview of epithelial ion-transport mechanisms

Shuttleworth¹

1989

Can. J. Zool.

View full text Add to dashboard Cite

SHUTTLEWORTH, T. J. 1989. Overview of epithelial ion-transport mechanisms. Can. J. Zool. 67: 3032-3038.The basic cellular transport mechanisms for the transepithelial uptake and elimination of sodium and chloride ions are briefly reviewed. These frequently involve processes defined as secondary active mechanisms, and the problems that this creates for their identification in epithelial systems are emphasised. It is suggested that despite the wide range of epithelial tissues involved in body fluid ion regulation, current evidence indicates that a relatively limited group of these secondary active carriers is involved in the transport process, and the basis for this evolutionary conservatism is discussed, together with certain of its implications. Finally, the interactions of the transport mechanisms with metabolic and acid-base parameters are contrasted in ion-uptake and ion-excretion situations, and the possible roles of carbonic anhydrase compared. SHUTTLEWORTH, T. J. 1989. Overview of epithelial ion-transport mechanisms. Can. J. Zool. 67 : 3032-3038.Les mCcanismes de base qui assurent le transport transCpithClia1 dans les cellules lors de l'absorption et de 1'Climination des ions sodium et des ions chlorure sont rCvisCs brikvement. Ces mCcanismes impliquent souvent des processus dCfinis comme des mCcanismes actifs secondaires et les problCmes que cela entrafne dans l'identification des systkmes CpithCliaux sont exposks. I1 semble qu'en dCpit de la grande variCtC de tissus CpithCliaux en cause dans la rCgulation ionique des fluides du corps, les travaux rCcents indiquent qu'un groupe relativement restreint de ces transporteurs secondaires actifs jouent un r61e dans le processus de transport. La raison de ce conservatisme Cvolutif et certaines de ses consCquences font l'objet d'une discussion. Enfin, les interactions entre, d'une part, les mCcanismes de transport et, d'autre part, les variables mCtaboliques et les variables qui jouent un r61e dans 1'Cquilibre acide -base, sont comparCes dans des conditions d'absorption et des conditions d'excrCtion d'ions; les r6les probables de l'anhydrase carbonique sont examinks.[Traduit par la revue] IntroductionThe purpose of this brief review is not to attempt to describe in detail all the different mechanisms of ion transport across animal cell me~nbranes, but to outline some current models describing the epithelial uptake and elimination of the principal ions of vertebrate animal body fluids, sodium and chloride, and to consider some of their implications. Particular attention will be paid to a discussion of certain consequences of the fact that these transport models frequently involve processes defined as secondary active mechanisms, and of the possible interactions of these ion-regulating systems with important metabolic and acid -base parameters.

show abstract

Chloride balance in Rana pipiens

Cited by 20 publications

References 0 publications

Kinetics of ionic transport across frog skin: Two concentration-dependent processes

Kinetics of ionic transport across frog skin: Two concentration-dependent processes

Effect of external cation and anion substitutions on sodium transport in isolated frog skin

Overview of epithelial ion-transport mechanisms

Contact Info

Product

Resources

About