Am J Physiol Cell Physiol AJP: Heart and Circulatory Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 281: C825-C832, 2001;
0363-6143/01 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (7)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Jennings, M. L.
Right arrow Articles by Adame, M. F.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Jennings, M. L.
Right arrow Articles by Adame, M. F.
Vol. 281, Issue 3, C825-C832, September 2001

Direct estimate of 1:1 stoichiometry of K+-Clminus cotransport in rabbit erythrocytes

Michael L. Jennings and Mark F. Adame

Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205

This work was undertaken to obtain a direct measure of the stoichiometry of Na+-independent K+-Cl- cotransport (KCC), with rabbit red blood cells as a model system. To determine whether 86Rb+ can be used quantitatively as a tracer for KCC, 86Rb+ and K+ effluxes were measured in parallel after activation of KCC with N-ethylmaleimide (NEM). The rate constant for NEM-stimulated K+ efflux into isosmotic NaCl was smaller than that for 86Rb+ by a factor of 0.68 ± 0.11 (SD, n = 5). This correction factor was used in all other experiments to calculate the K+ efflux from the measured 86Rb+ efflux. To minimize interference from the anion exchanger, extracellular Cl- was replaced with SO<UP><SUB>4</SUB><SUP>2−</SUP></UP>, and 4,4'-diisothiocyanothiocyanatodihydrostilbene-2,2'-disulfonic acid was present in the flux media. The membrane potential was clamped near 0 mV with the protonophore 2,4-dinitrophenol. The Cl- efflux at 25°C under these conditions is ~100,000-fold smaller than the uninhibited Cl-/Cl- exchange flux and is stimulated ~2-fold by NEM. The NEM-stimulated 36Cl- flux is inhibited by okadaic acid and calyculin A, as expected for KCC. The ratio of the NEM-stimulated K+ to Cl- efflux is 1.12 ± 0.26 (SD, n = 5). We conclude that K+-Cl- cotransport in rabbit red blood cells has a stoichiometry of 1:1.

red blood cells; N-ethylmaleimide; ion regulation


This article has been cited by other articles:


Home page
 J. Physiol.Home page
F. Bourgeois, M. J Coady, and J.-Y. Lapointe
Determination of transport stoichiometry for two cation-coupled myo-inositol cotransporters: SMIT2 and HMIT
J. Physiol., March 1, 2005; 563(2): 333 - 343.
[Abstract] [Full Text] [PDF]

Home page
 Physiol. Rev.Home page
V. L. Lew and R. M. Bookchin
Ion Transport Pathology in the Mechanism of Sickle Cell Dehydration
Physiol Rev, January 1, 2005; 85(1): 179 - 200.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Cell Physiol.Home page
J. R. Williams and J. A. Payne
Cation transport by the neuronal K+-Cl- cotransporter KCC2: thermodynamics and kinetics of alternate transport modes
Am J Physiol Cell Physiol, October 1, 2004; 287(4): C919 - C931.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Cell Physiol.Home page
E. Gagnon, B. Forbush, L. Caron, and P. Isenring
Functional comparison of renal Na-K-Cl cotransporters between distant species
Am J Physiol Cell Physiol, February 1, 2003; 284(2): C365 - C370.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online