Active and Passive Cation Transport and Its Association with Membrane Antigens in Sheep Erythrocytes

Lauf, Peter K.

doi:10.1007/978-1-4684-4082-9_71

Cited by 10 publications

(8 citation statements)

References 42 publications

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“…The thiol-dependent K/C1 transporter in LK sheep red cells fulfills the major criteria of a classic carrier system namely saturation kinetics [21], pronounced temperature dependence [21], and inhibition by anions other than C1-or Br- [18][19][20][21]. As previously shown, this transport system is capable of net fluxes which most probably constitute electroneutral movements of K + and C1-although firm evidence of stoichiometric coupling is still lacking.…”

Section: Discussionmentioning

confidence: 99%

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Thiol-Dependent passive K/Cl transport in sheep red cells: IV. Furosemide inhibition as a function of external Rb+, Na+, and Cl−

Lauf

1984

J. Membrain Biol.

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The effect of the loop diuretic furosemide (4-chloro-N-furfuryl-5-sulfamoyl-anthranilic acid) on the thiol-dependent, ouabain-insensitive K(Rb)/Cl transport in low K+ sheep red cells was studied at various concentrations of extracellular Rb+, Na+ and Cl-. In Rb+-free NaCl media, 2 X 10(-3) M furosemide inhibited only one-half of thiol-dependent K+ efflux. In the presence of 23 mM RbCl, however, the concentration of furosemide to produce 50% K+ efflux inhibition (IC50) was 5 X 10(-5) M. In Rb+ containing NaCl media, the inhibitory effect of 10(-3) M furosemide was equal to that caused by NO-3 replacement of Cl- in the medium. The apparent synergistic action of furosemide and external Rb+ on K+ efflux was also seen in the ouabain-insensitive Rb+ influx. A preliminary kinetic analysis suggests that furosemide binding alters both maximal K+(Rb+) transport and apparent external Rb+ affinity. In the presence of external Rb+, Na+ (as compared to choline) exerted a small but significant augmentation of the furosemide inhibition of K+(Rb+) fluxes. There was no effect of Cl- on the IC50 value of furosemide. As there is no evidence for coupled Na+K+ cotransport in low K+ sheep red cells, furosemide may modify thiol-dependent K+(Rb+)/Cl flux or Rb+ (and to a slight degree Na+) modulate the effect of furosemide.

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Section: Discussionmentioning

confidence: 99%

“…The NEM-activated K/C1 flux is usually 6 to 10 greater than the basal K/ C1 flux [21]. As there is also evidence for the presence of this thiol-dependent K/C1 transport system in reticulocytes of both HK and LK sheep [22], we have speculated on its role in the origin of the mature LK steady-state cell [18,19,22].…”

Section: Introductionmentioning

confidence: 99%

Thiol-Dependent passive K/Cl transport in sheep red cells: IV. Furosemide inhibition as a function of external Rb+, Na+, and Cl−

Lauf

1984

J. Membrain Biol.

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“…Replacement of Cl by Br-, F , I , NO;-and CNS-was based on simple equimolar substitution of NaC1 with the Na + salts of these anions. These antisera contain two anti-L antibodies, anti-Lp reacting with the Na+K + pump and anti-L~ reducing OR K + fluxes in LK cells [7,8,15,23]. In the immunological studies, a total of six different preparations of alloimmune anti-L sera obtained from Dr. B.A.…”

Section: Methodsmentioning

confidence: 99%

“…In the case of HCO~ a more elaborate procedure was necessary in order to maintain the pH between 7 and 8. As the present studies are concerned only with OR K + fluxes and the effect of anti-L~, only the terms Lvantibody and LFantigen will be used [15]. Rasmusen (Animal Genetics Laboratory, College of Agriculture, University of Illinois, Urbana, Ill.) and stored over years below -20~ were used following complement inactivation as described earlier [23].…”

Section: Methodsmentioning

confidence: 99%

Thiol-dependent passive K+Cl− transport in sheep red blood cells: VI. Functional heterogeneity and immunologic identity with volume-stimulated K+(Rb+) fluxes

Lauf

1984

J. Membrain Biol.

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Ouabain-resistant (OR), volume- or N-ethylmaleimide (NEM)-stimulated K+(Rb+)Cl- fluxes were measured in low-K+ sheep red cells and found to be functionally separate but immunologically similar. In anisosmotic solutions both K+ effluxes and Rb+ influxes of NEM-treated and control cells were additive. In contrast to the NEM-stimulated K+Cl- flux, metabolic depletion did not reduce K+Cl- flux of normal or swollen cells. The anion preference of OR K+ efflux in NEM-treated cells was Br- greater than Cl- greater than HCO3- = F- much greater than I- = NO3- = CNS-, and hence consistent with a reported Br- greater than Cl- greater than NO3- sequence of the volume-dependent K+Cl- transport. Alloimmune anti-L1 antibodies known to decrease passive K+ fluxes in low K+ cells reduced by 51% both volume- and NEM-stimulated, furosemide-sensitive Rb+Cl- fluxes suggesting their immunologic identity, a conclusion also supported by anti-L1 absorption studies. Since pretreatment with anti-L1 prevented the activation of Rb+ influx by NEM, and the impermeant glutathionmaleimide-I did not stimulate Rb+Cl- influx, the NEM reactive SH groups must be located apart from the L1 antigen either within the membrane or on its cytoplasmic face. A model is proposed consisting of a K+Cl- transport path(s) regulated by a protein with two functional subunits or domains: a chemically (Cs) and a volume (Vs)-stimulated domain, both interfacing with the L1 surface antigen. Attachment of alloanti-L1 from the outside reduces K+Cl- transport stimulated through Cs by NEM or Vs by cell swelling.

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“…A remarkable genetic association exists between the two cation steady states and two membrane surface antigens: The L antigens are located on LK and the M antigens on HK red ceils [34,39,40,46]. Much attention has been paid to explain the mechanism by which anti-L serum activates the kinetically different Na +, K + pumps in LK sheep and goat red cells [15,30,32], but progress in the area of passive cation permeabilities of the two cell types is only of very recent nature [9,10].…”

Section: Introductionmentioning

confidence: 99%

Thiol-dependent passive K/Cl transport in sheep red cells: I. Dependence on chloride and external K+[Rb+] ions

1983

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Treatment with 2 mM N-ethylmaleimide (NEM) caused a marked increase in K+ permeability of low K+ but not of high K+ sheep red cells suspended in isosmotic Cl- media with 10(-4) M ouabain. The Na+ permeability was unaltered. Kinetic analysis by K+ efflux and K+ or Rb+ influx measurements suggests that NEM primarily increased the bidirectional fluxes of K+ and Rb+, since (a) no significant change in the apparent external affinities of these ions was found, and (b) below unity, the observed flux ratios were close to those calculated from the Ussing relationship. Replacement of Cl- by NO3 abolished the NEM-stimulated and reduced the basal K+ flux rates. Similarly, 10(-3) M furosemide inhibited Cl- -dependent K+ fluxes in both control and NEM-treated LK red cells. Exposure of LK cells to hyposmotic but not to hyperosmotic salt solutions increased the basal Cl- dependent K+ flux twofold as reported by Dunham and Ellory (J. Physiol. (London) 318:511-530, 1981) but did not affect its fractional stimulation by NEM. The action of NEM is interpreted as a stimulation of a temperature-dependent and Cl- -requiring K+ transport pathway genetically preserved in adult LK but turned off in HK sheep red cells. In addition, common to both LK and HK sheep red cells was a basal K+ flux that operated in the presence of either Cl- or NO3-.

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Active and Passive Cation Transport and Its Association with Membrane Antigens in Sheep Erythrocytes

Cited by 10 publications

References 42 publications

Thiol-Dependent passive K/Cl transport in sheep red cells: IV. Furosemide inhibition as a function of external Rb+, Na+, and Cl−

Thiol-Dependent passive K/Cl transport in sheep red cells: IV. Furosemide inhibition as a function of external Rb+, Na+, and Cl−

Thiol-dependent passive K+Cl− transport in sheep red blood cells: VI. Functional heterogeneity and immunologic identity with volume-stimulated K+(Rb+) fluxes

Thiol-dependent passive K/Cl transport in sheep red cells: I. Dependence on chloride and external K+[Rb+] ions

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