The chloride/base exchanger in the basolateral cell membrane of rabbit renal proximal tubule S3 segment requires bicarbonate to operate

1990 ◽  
Vol 417 (1) ◽  
pp. 37-41 ◽  
Author(s):  
G. Seki ◽  
E. Fr�mter
Keyword(s):  
Cell Membrane ◽  
Proximal Tubule ◽  
Renal Proximal Tubule ◽  
Basolateral Cell Membrane ◽  
S3 Segment

Effect of parathyroid hormone on acid/base transport in rabbit renal proximal tubule S3 segment

1993 ◽  
Vol 423-423 (1-2) ◽  
pp. 7-13 ◽  
Author(s):  
George Seki ◽  
Shigeo Taniguchi ◽  
Shu Uwatoko ◽  
Keiji Suzuki ◽  
Kiyoshi Kurokawa
Keyword(s):  
Parathyroid Hormone ◽  
Proximal Tubule ◽  
Renal Proximal Tubule ◽  
Acid Base ◽  
S3 Segment

scholarly journals Evidence for conductive Cl- pathway in the basolateral membrane of rabbit renal proximal tubule S3 segment.

1993 ◽  
Vol 92 (3) ◽  
pp. 1229-1235 ◽  
Author(s):  
G Seki ◽  
S Taniguchi ◽  
S Uwatoko ◽  
K Suzuki ◽  
K Kurokawa
Keyword(s):  
Proximal Tubule ◽  
Basolateral Membrane ◽  
Renal Proximal Tubule ◽  
S3 Segment

Mechanism of anion permeation in the basolateral membrane of isolated rabbit renal proximal tubule S3 segment

1997 ◽  
Vol 272 (3) ◽  
pp. C837-C846 ◽  
Author(s):  
G. Seki ◽  
H. Yamada ◽  
S. Taniguchi ◽  
S. Uwatoko ◽  
K. Suzuki ◽  
...  
Keyword(s):  
Proximal Tubule ◽  
Channel Blocker ◽  
Basolateral Membrane ◽  
Renal Proximal Tubule ◽  
K Channel ◽  
Anion Selectivity ◽  
Anion Permeation ◽  
S3 Segment ◽  
Cl Conductance ◽  
Higher Sensitivity

Conventional and double-barreled microelectrodes were used to examine the anion selectivity of Cl- conductance in the basolateral membrane of rabbit renal proximal tubule S3 segment. The permeability sequence determined by anion replacements in the presence of K+ channel blocker quinine was SCN- > I- > Br- > Cl- > gluconate in both nonperfused and luminally perfused tubules. The anion-selective microelectrodes with higher sensitivity to I- enabled us to measure intracellular I- activities. With these electrodes, we could compare the conductive movements of Cl- and I- in response to the increase in bath K+ concentrations and confirmed that the conductance sequence was also I- > Cl-. Although the basolateral potential changes generated by Cl- and Br- currents were stimulated by adenosine 3',5'-cyclic monophosphate (cAMP), the potential changes by SCN- and I- currents were somewhat inhibited by cAMP. In addition, the conductive uptake of I- was, in contrast to that of Cl-, inhibited by cAMP These results are consistent with the existence of at least two distinct anion conductances in this membrane, which are differently regulated by cAMP.

Isolated perfused salamander proximal tubule: methods, electrophysiology, and transport

1981 ◽  
Vol 241 (1) ◽  
pp. F39-F52 ◽  
Author(s):  
H. Sackin ◽  
E. L. Boulpaep
Keyword(s):  
Cell Membrane ◽  
Proximal Tubule ◽  
Fluid Transport ◽  
Transference Number ◽  
Detailed Comparison ◽  
Proximal Tubules ◽  
Potential Difference ◽  
Ambystoma Tigrinum ◽  
Basolateral Cell Membrane

Techniques are presented for the isolation and perfusion of renal proximal tubules from the neotenic salamander Ambystoma tigrinum. Methods are described for a determination of normal values for fluid transport and electrophysiological parameters. Stable cellular microelectrode recordings are reported that constitute the first intracellular measurements in an isolated perfused tubule preparation. With identical solutions in lumen and bath, fluid reabsorption averaged 0.28 nl.min-1.mm-1, transepithelial potential difference averaged -4.5 mV, transepithelial resistance was 52.1 omega.cm2, and the transepithelial chloride-to-sodium transference number ratio was 3.4. The basolateral cell membrane potential difference averaged -59.6 mV, and the ratio of apical-to-basolateral cell membrane resistance was between 3.9 and 5. Viability of the isolated perfused salamander proximal tubule preparation is demonstrated by a detailed comparison of the present data with results of in vivo micropuncture experiments on both Necturus and intact Ambystoma kidneys. In addition to being an advantageous preparation for long-term intracellular recordings, the Ambystoma kidney is unique in that proximal tubules can be studied both in isolation and by conventional micropuncture.

Na+ electrochemical gradient and Na+-Ca2+ exchange in rat proximal tubule

1989 ◽  
Vol 257 (4) ◽  
pp. F531-F538
Author(s):  
J. H. Dominguez ◽  
J. K. Rothrock ◽  
W. L. Macias ◽  
J. Price
Keyword(s):  
Cell Membrane ◽  
Proximal Tubule ◽  
Thermodynamic Analysis ◽  
Cytosolic Calcium ◽  
Proximal Tubules ◽  
The Other ◽  
Electrochemical Gradient ◽  
Basolateral Cell Membrane ◽  
45Ca Efflux ◽  
Rat Proximal Tubule

he basolateral cell membrane of the rat proximal tubule contains a Na+-Ca2+ exchanger that may participate in the regulation of cytosolic calcium (Cai) and Ca2+ transport. In this work, the activity and orientation of the Na+-Ca2+ exchanger was studied in rat proximal tubules. The experiments were based on the thermodynamic notion that the exchanger is driven by the prevalence of either of two electrochemical gradients, that for Na+ (delta mu Na+) or for Ca2+ (delta mu Ca2+). Reductions in delta mu Na+, achieved by lowering extracellular Na+ (Nao) from 150 to 15 mM, increased Cai, decreased 45Ca efflux, and increased 45Ca influx. These changes occurred concurrently. When delta mu Na+ was reduced by increasing intracellular Na+ (Nai) with 10(-3) M oubain, Cai also increased. The effect of ouabain was probably dependent on Nai accumulation because the surge in Cai was prevented by exposure of the tubules to 5 mM Nao before ouabain exposure. On the other hand, when delta mu Na+ was lowered mM Nao and then by reducing Nao to 15 mM, Cai rose in two additive stages. We conclude from these data that in the rat proximal tubule the basal state of the Na+-Ca2+ exchanger is in forward mode, Nao-Cai. Moreover, the function of the Na+-Ca2+ exchanger is in accord with predictions derived from a thermodynamic analysis of its function.

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