AJP - Heart Calcium Transients and Cell-Sarcomere
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Heart Circ Physiol 266: H1103-H1111, 1994;
0363-6135/94 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
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 Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Altschuld, R. A.
Right arrow Articles by Brierley, G. P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Altschuld, R. A.
Right arrow Articles by Brierley, G. P.

AJP - Heart and Circulatory Physiology, Vol 266, Issue 3 1103-H1111, Copyright © 1994 by American Physiological Society

ARTICLES

Evidence against norepinephrine-stimulated efflux of mitochondrial Mg2+ from intact cardiac myocytes

R. A. Altschuld, D. W. Jung, R. M. Phillips, P. Narayan, L. C. Castillo, T. E. Whitaker, J. Hensley, C. M. Hohl and G. P. Brierley
Department of Medical Biochemistry, Ohio State University, Columbus 43210-1218.

We investigated the hypotheses that norepinephrine stimulates Mg2+ efflux from intact isolated adult rat ventricular cardiomyocytes and that adenosine 3',5'-cyclic monophosphate stimulates Mg2+ efflux from permeabilized myocytes and isolated mitochondria. Norepinephrine stimulation of Mg2+ release from cardiac myocytes was observed only when cells at approximately 20 mg protein/ml in Mg(2+)-containing buffer were diluted 50- to 60-fold into an Mg(2+)-free medium. Under these conditions, > 30% of total cellular lactic acid dehydrogenase activity was also released, indicating that a significant portion of the cells had died. In other protocols, where Mg2+ efflux from myocytes was not observed, extracellular Mg2+ removal and administration of 10 microM norepinephrine increased 45Ca2+ accumulation by cells in suspension. In single myocytes, Mg2+ removal and norepinephrine administration increased intracellular free [Ca2+] as measured by fura-2 fluorescence microscopy, and this was accompanied by vigorous spontaneous contractile activity followed by Ca2+ overload hypercontracture. With permeabilized myocytes and isolated mitochondria from a variety of sources, adenosine 3',5'-cyclic monophosphate did not stimulate Mg2+ efflux. These results suggest that recent evidence for direct hormonal regulation of myocardial Mg2+ homeostasis may need to be reevaluated.


This article has been cited by other articles:


Home page
 Circ. Res.Home page
E. Murphy
Mysteries of Magnesium Homeostasis
Circ. Res., February 18, 2000; 86(3): 245 - 248.
[Full Text] [PDF]

Home page
 Physiol. Rev.Home page
P. Bernardi
Mitochondrial Transport of Cations: Channels, Exchangers, and Permeability Transition
Physiol Rev, October 1, 1999; 79(4): 1127 - 1155.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
J. S. Rodriguez-Zavala and R. Moreno-Sanchez
Modulation of Oxidative Phosphorylation by Mg2+ in Rat Heart Mitochondria
J. Biol. Chem., April 3, 1998; 273(14): 7850 - 7855.
[Abstract] [Full Text] [PDF]

Home page
 Circ. Res.Home page
D. Keenan, A. Romani, and A. Scarpa
Differential Regulation of Circulating Mg2+ in the Rat by ß1- and ß2-Adrenergic Receptor Stimulation
Circ. Res., November 1, 1995; 77(5): 973 - 983.
[Abstract] [Full Text]


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