Skip Navigation

Cardiovascular Research 2002 53(2):334-340; doi:10.1016/S0008-6363(01)00501-6
© 2002 by European Society of Cardiology
This Article
Right arrow Full Text Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow E-letters: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when E-letters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Wei, S.-k.
Right arrow Articles by Haigney, M. C.P
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wei, S.-k.
Right arrow Articles by Haigney, M. C.P
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Copyright © 2001, European Society of Cardiology

Cytosolic free magnesium modulates Na/Ca exchange currents in pig myocytes

Shao-kui Weia, John F Quigleya, Stephen U Hanlona, Brian O'Rourkeb and Mark C.P Haigneya,*

aDivision of Cardiology, A-3060, Department of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
bInstitute of Molecular Cardiobiology, Johns Hopkins University, Baltimore, MD, USA

* Corresponding author. Tel.: +1-301-295-3826; fax: +1-301-295-3557 mcph{at}aol.com

Objective: Cardiac Na/Ca exchanger (NCX) protein is up-regulated and intracellular free magnesium ([Mg2+]i) is significantly reduced in experimental heart failure. We asked whether changes in [Mg2+]i in a physiologically relevant range could alter the INCX. Methods: The nickel-sensitive current was measured in voltage-clamped myocytes (Yorkshire pig; left ventricular) exposed to ramp pulses at 37°C in Tyrode's solution containing ouabain, nifedipine and ±Ni2+ (5 mmol/l). The intracellular free [Ca2+] and [Mg2+] concentrations were set at 50 nmol/l and 1.25 mmol/l (HiMg) or 0.13 mmol/l (LoMg), respectively, through pipette dialysis. Results: Reducing [Mg2+]i resulted in a significant increase in both outward and inward Ni-sensitive current without a shift in the reversal potential. This effect was not due to the inadvertent reduction of intracellular free [ATP] secondary to binding of ATP to Mg2+; reducing intracellular [ATP] in LoMg cells from 1.35 mmol/l to 0.18 mmol/l did not affect INCX. The intracellular free [Ca2+] was raised from 50 to 200 nmol/l, resulting in augmented inward and outward current due to calcium activation. HiMg attenuated both inward and outward currents significantly compared to LoMg, suggesting that [Mg2+]i competes with [Ca2+]i at the allosteric regulatory site. Conclusion: Cytosolic free magnesium modulates the INCX over a physiologic range independent of [ATP]i. Reduced [Mg2+]i in heart failure could contribute to altered calcium regulation of the NCX, contributing to the altered heart failure phenotype through enhanced NCX activity.

KEYWORDS Intra/extracellular ions; Ion channels; Myocytes; Na/Ca-exchanger

{star} Disclaimer: the views expressed in this paper reflect the opinions of the authors only and not the official policy of the Uniformed Services University or the Department of Defense.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 J. Biol. Chem.Home page
L. Boyman, H. Mikhasenko, R. Hiller, and D. Khananshvili
Kinetic and Equilibrium Properties of Regulatory Calcium Sensors of NCX1 Protein
J. Biol. Chem., March 6, 2009; 284(10): 6185 - 6193.
[Abstract] [Full Text] [PDF]

Home page
 JGPHome page
A. Yaradanakul, T.-M. Wang, V. Lariccia, M.-J. Lin, C. Shen, X. Liu, and D. W. Hilgemann
Massive Ca-induced Membrane Fusion and Phospholipid Changes Triggered by Reverse Na/Ca Exchange in BHK Fibroblasts
J. Gen. Physiol., July 1, 2008; 132(1): 29 - 50.
[Abstract] [Full Text] [PDF]

Home page
 JGPHome page
S. Brunet, T. Scheuer, R. Klevit, and W. A. Catterall
Modulation of CaV1.2 Channels by Mg2+ Acting at an EF-hand Motif in the COOH-terminal Domain
J. Gen. Physiol., September 26, 2005; 126(4): 311 - 323.
[Abstract] [Full Text] [PDF]

Home page
 J. Am. Coll. Nutr.Home page
A. P. Michailova, M. E. Belik, and A. D. McCulloch
Effects of Magnesium on Cardiac Excitation-Contraction Coupling
J. Am. Coll. Nutr., October 1, 2004; 23(5): 514S - 517S.
[Abstract] [Full Text] [PDF]

Home page
 HypertensionHome page
C. A. Northcott and S. W. Watts
Low [Mg2+]e Enhances Arterial Spontaneous Tone via Phosphatidylinositol 3-Kinase in DOCA-Salt Hypertension
Hypertension, January 1, 2004; 43(1): 125 - 129.
[Abstract] [Full Text] [PDF]

Home page
 Circ. Res.Home page
S.-k. Wei, A. Ruknudin, S. U. Hanlon, J. M. McCurley, D. H. Schulze, and M. C.P. Haigney
Protein Kinase A Hyperphosphorylation Increases Basal Current but Decreases {beta}-Adrenergic Responsiveness of the Sarcolemmal Na+-Ca2+ Exchanger in Failing Pig Myocytes
Circ. Res., May 2, 2003; 92(8): 897 - 903.
[Abstract] [Full Text] [PDF]

Home page
 Cardiovasc ResHome page
T. Kiyosue
Removal of intracellular Mg2+ activates cardiac Na+/Ca2+ exchanger
Cardiovasc Res, February 1, 2002; 53(2): 290 - 291.
[Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.