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 Izu, L. T.
Right arrow Articles by Balke, C. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Izu, L. T.
Right arrow Articles by Balke, C. W.

Biophys J, September 1998, p. 1144-1162, Vol. 75, No. 3

Theoretical Analysis of the Ca2+ Spark Amplitude Distribution

Leighton T. Izu,* W. Gil Wier,# and C. William Balke*#

 *Department of Medicine, Division of Cardiology, and  #Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201 USA

A difficulty of using confocal microscopy to study Ca2+ sparks is the uncertainty of the linescan position with respect to the source of Ca2+ release. Random placement of the linescan is expected to result in a broad distribution of measured Ca2+ spark amplitudes (a) even if all Ca2+ sparks were generated identically. Thus variations in Ca2+ spark amplitude due to positional differences between confocal linescans and Ca2+ release site are intertwined with variations due to intrinsic differences in Ca2+ release properties. To separate these two sources of variations on the Ca2+ spark amplitude, we determined the effect changes of channel current or channel open time---collectively called the source strength, alpha ---had on the measured Ca2+ spark amplitude histogram, N(a). This was done by 1) simulating Ca2+ release, Ca2+ and fluo-3 diffusion, and Ca2+ binding reactions; 2) simulation of image formation of the Ca2+ spark by a confocal microscope; and 3) using a novel automatic Ca2+ spark detector. From these results we derived an integral equation relating the probability density function of source strengths, falpha (alpha ), to N(a), which takes into account random positional variations between the source and linescan. In the special, but important, case that the spatial distribution of Ca2+-bound fluo-3 is Gaussian, we show the following: 1) variations of Ca2+ spark amplitude due to positional or intrinsic differences can be separated, and 2) falpha (alpha ) can, in principle, be calculated from the Ca2+ spark amplitude histogram since N(a) is the sum of shifted hyperbolas, where the magnitudes of the shifts and weights depend on falpha (alpha ). In particular, if all Ca2+ sparks were generated identically, then the plot of 1/N(a) against a will be a straight line. Multiple populations of channels carrying distinct currents are revealed by discontinuities in the 1/N(a) plot. 3) Although the inverse relationship between Ca2+ spark amplitude and decay time might be used to distinguish Ca2+ sparks from different channel populations, noise can render the measured decay times meaningless for small amplitude Ca2+ sparks.

Biophys J, September 1998, p. 1144-1162, Vol. 75, No. 3
© 1998 by the Biophysical Society   0006-3495/98/09/1144/19  $2.00


This article has been cited by other articles:


Home page
 Biophys. JHome page
L. T. Izu, T. Banyasz, C. W. Balke, and Y. Chen-Izu
Eavesdropping on the Social Lives of Ca2+ Sparks
Biophys. J., November 15, 2007; 93(10): 3408 - 3420.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
T. Banyasz, Y. Chen-Izu, C. W. Balke, and L. T. Izu
A New Approach to the Detection and Statistical Classification of Ca2+ Sparks
Biophys. J., June 15, 2007; 92(12): 4458 - 4465.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
A. Zahradnikova Jr, E. Polakova, I. Zahradnik, and A. Zahradnikova
Kinetics of calcium spikes in rat cardiac myocytes
J. Physiol., February 1, 2007; 578(3): 677 - 691.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
Y. Chen-Izu, S. L. McCulle, C. W. Ward, C. Soeller, B. M. Allen, C. Rabang, M. B. Cannell, C. W. Balke, and L. T. Izu
Three-Dimensional Distribution of Ryanodine Receptor Clusters in Cardiac Myocytes
Biophys. J., July 1, 2006; 91(1): 1 - 13.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
F. v. Wegner, M. Both, and R. H. A. Fink
Automated Detection of Elementary Calcium Release Events Using the A Trous Wavelet Transform
Biophys. J., March 15, 2006; 90(6): 2151 - 2163.
[Abstract] [Full Text] [PDF]

Home page
 Circ. Res.Home page
S.-Q. Wang, C. Wei, G. Zhao, D. X.P. Brochet, J. Shen, L.-S. Song, W. Wang, D. Yang, and H. Cheng
Imaging Microdomain Ca2+ in Muscle Cells
Circ. Res., April 30, 2004; 94(8): 1011 - 1022.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
S. P. Parsons and T. B. Bolton
Localised calcium release events in cells from the muscle of guinea-pig gastric fundus
J. Physiol., February 1, 2004; 554(3): 687 - 705.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
J.-X. Shen, S. Wang, L.-S. Song, T. Han, and H. Cheng
Polymorphism of Ca2+ Sparks Evoked from In-Focus Ca2+ Release Units in Cardiac Myocytes
Biophys. J., January 1, 2004; 86(1): 182 - 190.
[Abstract] [Full Text] [PDF]

Home page
 Circ. Res.Home page
C. Lamont and W. G. Wier
Evoked and Spontaneous Purinergic Junctional Ca2+ Transients (jCaTs) in Rat Small Arteries
Circ. Res., September 20, 2002; 91(6): 454 - 456.
[Abstract] [Full Text] [PDF]

Home page
 J. Gen. Physiol.Home page
S.M. Baylor, S. Hollingworth, and W.K. Chandler
Comparison of Simulated and Measured Calcium Sparks in Intact Skeletal Muscle Fibers of the Frog
J. Gen. Physiol., August 26, 2002; 120(3): 349 - 368.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
J.-W. Shuai and P. Jung
Stochastic Properties of Ca2+ Release of Inositol 1,4,5-Trisphosphate Receptor Clusters
Biophys. J., July 1, 2002; 83(1): 87 - 97.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
S.-Q. Wang, L.-S. Song, L. Xu, G. Meissner, E. G. Lakatta, E. Rios, M. D. Stern, and H. Cheng
Thermodynamically Irreversible Gating of Ryanodine Receptors in Situ Revealed by Stereotyped Duration of Release in Ca2+ Sparks
Biophys. J., July 1, 2002; 83(1): 242 - 251.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
W. G. Wier, C. W. Balke, J. A. Michael, and J. R. H. Mauban
A custom confocal and two-photon digital laser scanning microscope
Am J Physiol Heart Circ Physiol, June 1, 2000; 278(6): H2150 - H2156.
[Abstract] [Full Text] [PDF]

Home page
 Circ. Res.Home page
W. G. Wier and C. W. Balke
Ca2+ Release Mechanisms, Ca2+ Sparks, and Local Control of Excitation-Contraction Coupling in Normal Heart Muscle
Circ. Res., October 29, 1999; 85(9): 770 - 776.
[Full Text] [PDF]

Home page
 Circ. Res.Home page
S. R. Shorofsky, R. Aggarwal, M. Corretti, J. M. Baffa, J. M. Strum, B. A. Al-Seikhan, Y. M. Kobayashi, L. R. Jones, W. G. Wier, and C. W. Balke
Cellular Mechanisms of Altered Contractility in the Hypertrophied Heart : Big Hearts, Big Sparks
Circ. Res., March 5, 1999; 84(4): 424 - 434.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
A. Gonzalez, W. G. Kirsch, N. Shirokova, G. Pizarro, G. Brum, I. N. Pessah, M. D. Stern, H. Cheng, and E. Rios
Involvement of multiple intracellular release channels in calcium sparks of skeletal muscle
PNAS, April 11, 2000; 97(8): 4380 - 4385.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1998 by the Biophysical Society.