Taurine transport by rabbit kidney brush-border membranes: Coupling to sodium, chloride, and the membrane potential

1988 ◽  
Vol 102 (2) ◽  
pp. 131-139 ◽  
Author(s):  
N. A. Wolff ◽  
R. Kinne
Keyword(s):  
Membrane Potential ◽  
Sodium Chloride ◽  
Brush Border ◽  
Rabbit Kidney ◽  
Taurine Transport ◽  
Brush Border Membranes

Nicotinic acid transport by brush border membrane vesicles from rabbit kidney

1981 ◽  
Vol 240 (3) ◽  
pp. F185-F191 ◽  
Author(s):  
E. F. Boumendil-Podevin ◽  
R. A. Podevin
Keyword(s):  
Membrane Potential ◽  
Nicotinic Acid ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Isonicotinic Acid ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Rabbit Kidney ◽  
Internal Space ◽  
Acid Uptake

The transport of nicotinic acid was investigated in brush border membrane vesicles isolated from rabbit kidney. The imposition of a Na+ gradient (out to in) induced a transient stimulation of nicotinic acid uptake above its final equilibrium value. This stimulation was specific for Na+. The uptake of nicotinic acid by the brush border membranes represented transport into an internal space and occurred in the absence of significant nicotinic acid degradation. The Na+ gradient-dependent uptake of nicotinic acid was saturable, apparent Km = 0.3 mM. Uptake of nicotinic acid was inhibited by its two isomers: picolinic and isonicotinic acid. In contrast, pyridine derivatives with two carboxyl groups or an amide group in addition to the carboxyl group were without inhibitory effect. Evaluation of changes in membrane potential using the lipophilic cation triphenylmethylphosphonium demonstrated that conditions that transiently generated either an interior-positive or an interior-negative membrane potential failed to affect the Na+-dependent transport of nicotinic acid. These findings provide evidence of the existence on the luminal membrane of a Na+ gradient-dependent and electroneutral transport system for nicotinic acid.

Characteristics of renal transport of taurine in reptilian brush-border membranes

1991 ◽  
Vol 260 (5) ◽  
pp. R879-R888 ◽  
Author(s):  
S. Benyajati ◽  
J. L. Johnson
Keyword(s):  
Brush Border ◽  
Thamnophis Sirtalis ◽  
Equilibrium Conditions ◽  
Taurine Transport ◽  
Brush Border Membranes ◽  
Renal Brush Border Membranes ◽  
Negative Membrane Potential ◽  
Taurine Uptake ◽  
Filtration Technique

We examined characteristics of taurine transport across renal brush-border membranes (BBM) of the garter snake (Thamnophis sirtalis), a species that demonstrates both net reabsorption and secretion of taurine in vivo. Transport was examined by a rapid filtration technique at 25 degrees C. Inwardly directed Na+ gradient specifically stimulated taurine uptake. Under initial taurine equilibrium condition, a small overshoot of taurine uptake driven by an inwardly directed NaCl gradient could be observed. No stimulation of taurine uptake was observed under Na+ equilibrium or K+, Li+, or choline gradients conditions. Reptilian renal BBM taurine transport also displayed specific Cl- requirement: replacement of NaCl by NaSCN or Na(+)-gluconate gradients inhibited taurine uptake. The uptake was stimulated under Cl- gradient compared with Cl- equilibrium conditions. Taurine transport was not stimulated by H+ gradient in either direction, although it was inhibited by acidic pH (less than 7.0). Amiloride and furosemide had no effects. The transport was electrogenic, stimulated by an inside negative membrane potential, and inhibited by other beta-amino acids. Overall, the reptilian BBM transport system for taurine resembles those observed in both mammalian and fish renal BBM.

scholarly journals Atrial peptide inactivation by rabbit-kidney brush-border membranes

1987 ◽  
Vol 170 (1-2) ◽  
pp. 431-434 ◽  
Author(s):  
Gillian M. OLINS ◽  
Kerry L. SPEAR ◽  
Ned R. SIEGEL ◽  
Emily J. REINHARD ◽  
Heidi A. ZURCHER-NEELY
Keyword(s):  
Brush Border ◽  
Rabbit Kidney ◽  
Brush Border Membranes

scholarly journals Reconstitution and characterization of a Na+/Pi co-transporter protein from rabbit kidney brush-border membranes

1992 ◽  
Vol 286 (1) ◽  
pp. 97-102 ◽  
Author(s):  
H Debiec ◽  
R Lorenc ◽  
P M Ronco
Keyword(s):  
Molecular Mass ◽  
Brush Border ◽  
Broad Band ◽  
Gel Filtration ◽  
Phosphate Transport ◽  
Rabbit Kidney ◽  
Dilution Method ◽  
Native Form ◽  
Brush Border Membranes ◽  
Transporter Protein

A protein with Na+/Pi co-transporter activity has been extracted from rabbit brush-border membranes with chloroform/methanol and purified by hydroxyapatite chromatography. The protein has been incorporated by the dilution method into liposomes formed from different types and ratios of lipids. The greatest reconstitution has been achieved into liposomes prepared from cholesterol (20%), phosphatidylcholine (20%), phosphatidylethanolamine (30%) and phosphatidylserine (30%) (CH/PC/PE/PS). Pi uptake by these proteoliposomes had the following characteristics: (i) the initial rate was markedly greater in the presence of an inwardly directed Na+ gradient (600 pmol/10 s per mg) than with a K+ gradient (65 pmol/10 s per mg); (ii) maximal uptake was increased 8-fold above the equilibrium value (‘overshoot’) when a Na+ gradient was applied; (iii) Pi was not merely bound to proteoliposomes but was transported intravesicularly; and (iv) Na(+)-dependent Pi uptake was sensitive to the known phosphate transport inhibitors. This first successful attempt of reconstitution of Na+/Pi transport activity into proteoliposomes led us to isolate and characterize physico-chemically the protein responsible. Its isoelectric point was about 5.8, and urea/SDS gel electrophoresis revealed a broad band of molecular mass ranging from 63 to 66 kDa under both reducing and non-reducing conditions. In the native form, the molecular mass analysed by gel filtration was estimated to be 170 +/- 10 kDa, suggesting that the protein is a polymer, probably stabilized by hydrophobic bonds. Endoglycosidase F treatment decreased the molecular mass to approx. 50 kDa. It is postulated that this acidic glycoprotein might represent a subunit of the intact Na+/Pi co-transporter from rabbit kidney brush-border membranes.

scholarly journals Electrogenicity of phosphate transport by renal brush-border membranes

1988 ◽  
Vol 252 (3) ◽  
pp. 801-806 ◽  
Author(s):  
R Béliveau ◽  
H Ibnoul-Khatib
Keyword(s):  
Membrane Potential ◽  
Brush Border ◽  
Phosphate Uptake ◽  
Electrical Potential ◽  
Membrane Potentials ◽  
Experimental Conditions ◽  
Brush Border Membranes ◽  
Renal Brush Border Membrane ◽  
Renal Brush Border Membranes ◽  
Renal Brush Border

Phosphate uptake by rat renal brush-border membrane vesicles was studied under experimental conditions where transmembrane electrical potential (delta psi) could be manipulated. Experiments were performed under initial rate conditions to avoid complications associated with the dissipation of ion gradients. First, phosphate uptake was shown to be strongly affected by the nature of Na+ co-anions, the highest rates of uptake being observed with 100 mM-NaSCN (1.010 +/- 0.086 pmol/5 s per micrograms of protein) and the lowest with 50 mM-Na2SO4 (0.331 +/- 0.046 pmol/5 s per micrograms of protein). Anion substitution studies showed that potency of the effect of the co-anions was in the order thiocyanate greater than nitrate greater than chloride greater than isethionate greater than gluconate greater than sulphate, which correlates with the known permeability of the membrane to these anions and thus to the generation of transmembrane electrical potentials of decreasing magnitude (inside negative). The stimulation by ion-diffusion-induced potential was observed from pH 6.5 to 8.5, indicating that the transport of both monovalent and divalent phosphate was affected. In addition, inside-negative membrane potentials were generated by valinomycin-induced diffusion of K+ from K+-loaded vesicles and showed a 57% stimulation of phosphate uptake, at pH 7.5. Similar experiments with H+-loaded vesicles, in the presence of carbonyl cyanide m-chlorophenylhydrazone gave a 50% stimulation compared with controls. Inside-positive membrane potentials were also induced by reversal of the K+ gradient (outside greater than inside) in the presence of valinomycin and gave 58% inhibition of phosphate uptake. The membrane-potential dependency of phosphate uptake was finally analysed under thermodynamic equilibrium, and a stimulation by inside-negative potential was observed. The transport of phosphate was thus driven against a concentration gradient by a membrane potential, implicating the net transfer of a positive charge during the translocation process. These results indicate a major contribution of electrical potential to phosphate uptake in renal brush-border membranes.

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