AJP - GI Watch the video to see how APS reaches out to developing nations.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Gastrointest Liver Physiol 278: G400-G408, 2000;
0193-1857/00 $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 ISI 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 ISI Web of Science (30)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Schweigel, M.
Right arrow Articles by Martens, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Schweigel, M.
Right arrow Articles by Martens, H.
Vol. 278, Issue 3, G400-G408, March 2000

Mechanisms of Mg2+ transport in cultured ruminal epithelial cells

Monika Schweigel1, Jürgen Vormann2, and Holger Martens1

1 Department of Veterinary Physiology, Free University of Berlin, 14163 Berlin; and 2 Department of Molecular Biology and Biochemistry, Free University of Berlin, 14195 Berlin, Germany

Net Mg2+ absorption from the rumen is mainly mediated by a transcellular pathway, with the greater part (62%) being electrically silent. To investigate this component of Mg2+ transport, experiments were performed with isolated ruminal epithelial cells (REC). Using the fluorescent indicators mag-fura 2, sodium-binding benzofuran isophthalate, and 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, we measured the intracellular free Mg2+ concentration ([Mg2+]i), the intracellular Na+ concentration ([Na+]i), and the intracellular pH (pHi) of REC under basal conditions, after stimulation with butyrate and HCO-3, and after changing the transmembrane chemical gradients for Mg2+, H+, and Na+. REC had a mean resting pHi of 6.83 ± 0.1, [Mg2+]i was 0.56 ± 0.14 mM, and [Na+]i was 18.95 ± 3.9 mM. Exposure to both HCO-3 and HCO-3/butyrate led to a stimulation of Mg2+ influx that amounted to 27.7 ± 5 and 29 ± 10.6 µM/min, respectively, compared with 15 ± 1 µM/min in control solution. The increase of [Mg2+]i was dependent on extracellular Mg2+ concentration ([Mg2+]e). Regulation of pHi has been demonstrated to be Na+ dependent and is performed, for the most part, by a Na+/H+ exchanger. The recovery of pHi was fully blocked in nominally Na+-free media, even if [Mg2+]e was stepwise increased from 0 to 7.5 mM. However, an increase of [Mg2+]i was observed after reversing the transmembrane Na+ gradient. This rise in [Mg2+]i was pH independent, K+ insensitive, dependent on [Mg2+]e, imipramine and quinidine sensitive, and accompanied by a decrease of [Na+]i. The results are consistent with the existence of a Na+/Mg2+ exchanger in the cell membrane of REC. The coupling between butyrate, CO2/HCO-3, and Mg2+ transport may be mediated by another mechanism, perhaps by cotransport of Mg2+ and HCO-3.

sheep rumen; epithelial cells; magnesium transport; intracellular magnesium; sodium/magnesium antiport; mag-fura 2


This article has been cited by other articles:


Home page
 Exp PhysiolHome page
S.-J. Kim, S.-J. Lee, J.-S. Kim, and H.-S. Kang
High extracellular [Mg2+]-induced increase in intracellular [Mg2+] and decrease in intracellular [Na+] are associated with activation of p38 MAP kinase and ERK2 in guinea-pig heart
Exp Physiol, December 1, 2008; 93(12): 1223 - 1232.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Gastrointest. Liver Physiol.Home page
B. Etschmann, K. S. Heipertz, A. von der Schulenburg, and M. Schweigel
A vH+-ATPase is present in cultured sheep ruminal epithelial cells
Am J Physiol Gastrointest Liver Physiol, December 1, 2006; 291(6): G1171 - G1179.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Gastrointest. Liver Physiol.Home page
M. Schweigel, H.-S. Park, B. Etschmann, and H. Martens
Characterization of the Na+-dependent Mg2+ transport in sheep ruminal epithelial cells
Am J Physiol Gastrointest Liver Physiol, January 1, 2006; 290(1): G56 - G65.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Gastrointest. Liver Physiol.Home page
K. Abdoun, F. Stumpff, K. Wolf, and H. Martens
Modulation of electroneutral Na transport in sheep rumen epithelium by luminal ammonia
Am J Physiol Gastrointest Liver Physiol, September 1, 2005; 289(3): G508 - G520.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
D. Gunzel, K. Hintz, S. Durry, and W.-R. Schlue
Mg2+-Malate Co-Transport, a Mechanism for Na+-Independent Mg2+ Transport in Neurons of the Leech Hirudo medicinalis
J Neurophysiol, July 1, 2005; 94(1): 441 - 453.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Gastrointest. Liver Physiol.Home page
S. Leonhard-Marek, F. Stumpff, I. Brinkmann, G. Breves, and H. Martens
Basolateral Mg2+/Na+ exchange regulates apical nonselective cation channel in sheep rumen epithelium via cytosolic Mg2+
Am J Physiol Gastrointest Liver Physiol, April 1, 2005; 288(4): G630 - G645.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Gastrointest. Liver Physiol.Home page
M. Schweigel and H. Martens
Anion-dependent Mg2+ influx and a role for a vacuolar H+-ATPase in sheep ruminal epithelial cells
Am J Physiol Gastrointest Liver Physiol, June 9, 2003; 285(1): G45 - G53.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
A. Graschopf, J. A. Stadler, M. K. Hoellerer, S. Eder, M. Sieghardt, S. D. Kohlwein, and R. J. Schweyen
The Yeast Plasma Membrane Protein Alr1 Controls Mg2+ Homeostasis and Is Subject to Mg2+-dependent Control of Its Synthesis and Degradation
J. Biol. Chem., May 4, 2001; 276(19): 16216 - 16222.
[Abstract] [Full Text] [PDF]


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