|
|
|
|
|
|
|
||
J. Gen. Physiol.,
Volume 113, Number 2, February 1, 1999 187-198
From the Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201-1503
Discrete Ca2+ release events (Ca2+ "sparks") were recorded in cut segments of single frog skeletal
muscle fibers using a video-rate laser-scanning confocal microscope operating in line-scan mode (63 µs per line).
Fibers loaded with the Ca2+ indicator fluo-3 were voltage clamped at a holding potential of 0 mV, briefly reprimed
at 
90 mV, and then strongly depolarized with a large test pulse to activate any reprimed voltage sensors. Using
this high time resolution system, it was possible to record individual Ca2+ sparks at ~30-fold higher time resolution than previously attained. The resulting new experimental data provides a means of characterizing the time
course of fluorescence during the brief (a few milliseconds) rising phase of a spark, which was not possible with
the previously used 1.5-2 ms per line confocal systems. Analysis of the time course of individual identified events
indicates that fluorescence begins to rise rather abruptly at the start of the spark, continues to rise at a slightly decreasing rate to a relatively sharp peak, and then declines along a quasi-exponential time course. The mean rise
time of 198 sparks was 4.7 ± 0.1 ms, and there was no correlation between rise time and peak amplitude. Average
sparks constructed by temporally and spatially superimposing and summing groups of individual sparks having
similar rise times gave a lower noise representation of the sparks, consistent with the time course of individual
events. In theory, the rising phase of a spark provides a lower bound estimation of the time that Ca2+ ions are being released by the sarcoplasmic reticulum Ca2+ channel(s) generating the spark. The observed time course of fluorescence suggests that the Ca2+ release underlying a spark could continue at a fairly constant rate throughout the
rising phase of the spark, and then stop rather abruptly at the time of the peak.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  R. Bao, L. M. Lifshitz, R. A. Tuft, K. Bellve, K. E. Fogarty, and R. ZhuGe A Close Association of RyRs with Highly Dense Clusters of Ca2+-activated Cl- Channels Underlies the Activation of STICs by Ca2+ Sparks in Mouse Airway Smooth Muscle J. Gen. Physiol., July 1, 2008; 132(1): 145 - 160. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Rios, J. Zhou, G. Brum, B. S. Launikonis, and M. D. Stern Calcium-dependent Inactivation Terminates Calcium Release in Skeletal Muscle of Amphibians J. Gen. Physiol., March 31, 2008; 131(4): 335 - 348. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 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]
|
|
|
|
|
|
S. Hollingworth, W. K. Chandler, and S. M. Baylor Effects of Tetracaine on Voltage-activated Calcium Sparks in Frog Intact Skeletal Muscle Fibers J. Gen. Physiol., February 27, 2006; 127(3): 291 - 307. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. S. Launikonis, J. Zhou, L. Royer, T. R. Shannon, G. Brum, and E. Rios Depletion "skraps" and dynamic buffering inside the cellular calcium store PNAS, February 21, 2006; 103(8): 2982 - 2987. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Zhou, G. Brum, A. Gonzalez, B. S. Launikonis, M. D. Stern, and E. Rios Concerted vs. Sequential. Two Activation Patterns of Vast Arrays of Intracellular Ca2+ Channels in Muscle J. Gen. Physiol., September 26, 2005; 126(4): 301 - 309. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Zhang, G. G. Rodney, and M. F. Schneider Effects of Azumolene on Ca2+ Sparks in Skeletal Muscle Fibers J. Pharmacol. Exp. Ther., July 1, 2005; 314(1): 94 - 102. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Terentyev, S. Viatchenko-Karpinski, I. Gyorke, P. Volpe, S. C. Williams, and S. Gyorke Calsequestrin determines the functional size and stability of cardiac intracellular calcium stores: Mechanism for hereditary arrhythmia PNAS, September 30, 2003; 100(20): 11759 - 11764. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Zhou, G. Brum, A. Gonzalez, B.S. Launikonis, M.D. Stern, and E. Rios Ca2+ Sparks and Embers of Mammalian Muscle. Properties of the Sources J. Gen. Physiol., June 30, 2003; 122(1): 95 - 114. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W.K. Chandler, S. Hollingworth, and S.M. Baylor Simulation of Calcium Sparks in Cut Skeletal Muscle Fibers of the Frog J. Gen. Physiol., March 31, 2003; 121(4): 311 - 324. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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]
|
|
|
|
|
|
D V Gordienko and T B Bolton Crosstalk between ryanodine receptors and IP3 receptors as a factor shaping spontaneous Ca2+-release events in rabbit portal vein myocytes J. Physiol., August 1, 2002; 542(3): 743 - 762. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. S. Hui, K. R Bidasee, and H. R Besch Jr Effects of ryanodine on calcium sparks in cut twitch fibres of Rana temporaria J. Physiol., July 15, 2001; 534(2): 327 - 342. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. I. McDonough, Z. Cseresnyes, and M. F. Schneider Origin Sites of Calcium Release and Calcium Oscillations in Frog Sympathetic Neurons J. Neurosci., December 15, 2000; 20(24): 9059 - 9070. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Brum, A. Gonzalez, J. Rengifo, N. Shirokova, and E. Rios Fast imaging in two dimensions resolves extensive sources of Ca2+ sparks in frog skeletal muscle J. Physiol., November 1, 2000; 528(3): 419 - 433. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Lacampagne, M. G. Klein, C. W. Ward, and M. F. Schneider Two mechanisms for termination of individual Ca2+ sparks in skeletal muscle PNAS, July 5, 2000; 97(14): 7823 - 7828. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. H. Jaggar, V. A. Porter, W. J. Lederer, and M. T. Nelson Calcium sparks in smooth muscle Am J Physiol Cell Physiol, February 1, 2000; 278(2): C235 - C256. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. G Klein, A. Lacampagne, and M. F Schneider A repetitive mode of activation of discrete Ca2+ release events (Ca2+ sparks) in frog skeletal muscle fibres J. Physiol., March 1, 1999; 515(2): 391 - 411. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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]
|
|
|
|
