help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
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
Services
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
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bazzazi, H.
Right arrow Articles by Kargacin, G. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bazzazi, H.
Right arrow Articles by Kargacin, G. J.
Biophysical Journal 85:1754-1765 (2003)
© 2003 The Biophysical Society

Ca2+ Regulation in the Near-Membrane Microenvironment in Smooth Muscle Cells

Hojjat Bazzazi, Margaret E. Kargacin and Gary J. Kargacin

Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, Canada

Correspondence: Address reprint requests to Dr. Gary J. Kargacin, Dept. of Physiology and Biophysics, University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta T2N 4N1 Canada. Tel.: 403-220-3873; Fax: 403-270-2211; E-mail: kargacin{at}ucalgary.ca.

The microenvironment between the plasma membrane and the near-membrane sarcoplasmic reticulum (SR) may play an important role in Ca2+ regulation in smooth muscle cells. We used a three-dimensional mathematical model of Ca2+ diffusion and regulation and experimental measurements of SR Ca2+ uptake and the distribution of the SR in isolated smooth muscle cells to predict the extent that the near-membrane SR could load Ca2+ after the opening of single plasma membrane Ca2+ channels. We also modeled the effect of SR uptake on 1), single-channel Ca2+ transients in the near-membrane space; 2), the association of Ca2+ with Ca2+ buffers in this space; and 3), the amount of Ca2+ reaching the central cytoplasm of the cell. Our results indicate that, although single-channel Ca2+ transients could increase SR Ca2+ to a certain extent, SR Ca2+ uptake is not rapid enough to greatly affect the magnitude of these transients or their spread to the central cytoplasm unless the Ca2+ uptake rate of the peripheral SR is an order-of-magnitude higher than the mean rate derived from our experiments. Immunofluorescence imaging, however, did not reveal obvious differences in the density of SR Ca2+ pumps or phospholamban between the peripheral and central SR in smooth muscle cells.




This article has been cited by other articles:


Home page
 Biophys. JHome page
P. P. Jones, H. Bazzazi, G. J. Kargacin, and J. Colyer
Inhibition of cAMP-Dependent Protein Kinase under Conditions Occurring in the Cardiac Dyad during a Ca2+ Transient
Biophys. J., July 15, 2006; 91(2): 433 - 443.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
G. Lemon, J. Brockhausen, G.-H. Li, W. G. Gibson, and M. R. Bennett
Calcium Mobilization and Spontaneous Transient Outward Current Characteristics upon Agonist Activation of P2Y2 Receptors in Smooth Muscle Cells
Biophys. J., March 1, 2005; 88(3): 1507 - 1523.
[Abstract] [Full Text] [PDF]

Home page
 Pharmacol. Rev.Home page
R. Laporte, A. Hui, and I. Laher
Pharmacological Modulation of Sarcoplasmic Reticulum Function in Smooth Muscle
Pharmacol. Rev., December 1, 2004; 56(4): 439 - 513.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2003 by the Biophysical Society.