HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Supplemental data All Versions of this Article: 578/3/677    most recent jphysiol.2006.117796v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Zahradníková, A. Articles by Zahradníková, A. Search for Related Content PubMed PubMed Citation Articles by Zahradníková, A., Jr Articles by Zahradníková, A. Related Collections Cellular

¹ Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlárska 5, Bratislava, Slovak Republic

The local calcium release flux signals (calcium spikes) evoked by membrane depolarization were recorded at high temporal resolution (2000 lines s^–1) in isolated ventricular myocytes of male rats, using combination of scanning confocal microscopy and the patch-clamp technique. The kinetic properties of calcium spikes were investigated. The time course of calcium spike activation could be described reliably by a model with higher-order (n = 3) kinetics, but not by a first-order exponential process. A model of calcium spike with calcium release termination coupled to its activation was preferential to a model with the release termination independent of its activation. Three fluorescent calcium dyes (OG-5N, fluo-3, and fluo-4) were compared for calcium spike measurements. Experimental measurements as well as simulations showed that the occurrence and latency of calcium spikes could be measured faithfully with all indicators, while the kinetics of calcium spikes was reliably traced only with OG-5N. Calcium spikes evoked by a step depolarization from –50 to 0 mV commenced with a mean latency of 4.1 ± 0.2 ms and peaked 6.7 ± 0.2 ms later. Their full amplitudes were normally distributed. The activation time constant of calcium spikes was 3.1 ± 0.1 ms, and the time constant of termination was 5.5 ± 0.2 ms. A negative correlation was observed between the observed amplitude of calcium spikes and their time constant of activation, but there was no correlation between their observed amplitude and time constant of termination, in agreement with the concept of steep calcium-dependent activation and fateful inactivation of calcium release flux.

(Received 21 July 2006; accepted after revision 14 November 2006; first published online 23 November 2006)
Corresponding author A. Zahradníková: Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlárska 5, Bratislava, Slovak Republic.  Email: alexandra.zahradnikova{at}savba.sk

This article has been cited by other articles:

				E. Polakova, A. Zahradnikova Jr, J. Pavelkova, I. Zahradnik, and A. Zahradnikova Local calcium release activation by DHPR calcium channel openings in rat cardiac myocytes J. Physiol., August 15, 2008; 586(16): 3839 - 3854. [Abstract] [Full Text] [PDF]

				C. Chantawansri, N. Huynh, J. Yamanaka, A. Garfinkel, S. T. Lamp, M. Inoue, J. H. B. Bridge, and J. I. Goldhaber Effect of Metabolic Inhibition on Couplon Behavior in Rabbit Ventricular Myocytes Biophys. J., March 1, 2008; 94(5): 1656 - 1666. [Abstract] [Full Text] [PDF]