[Frontiers in Bioscience 7, d1288-1297, May 1, 2002]

CALCIUM QUARKS

Ernst Niggli, Marcel Egger

Department of Physiology, University of Bern, Bühlplatz 5, 3012 Bern, Switzerland

TABLE OF CONTENTS

1.Abstract

2.Introduction
2.1.Why is the elementary nature of Ca2+ signaling important?
2.2.Why is the precise number of channels participating in the generation of Ca2+sparks important?
3.Definition of a Ca2+ quark
4.SR Ca2+release activated by UV-flash photolysis
5.SR Ca2+release activated by two-photon photolysis
6.SR Ca2+release activated by Na-Ca exchange running in the Ca2+ influx mode
7.Elementary SR Ca2+ release signals in skeletal muscle
8.Ca2+ release signals in a heterologous expression system
9.Perspective
10.Acknowledgements
11.References

1. ABSTRACT

Elementary subcellular Ca2+ signals arising from the opening of single ion channels may offer the possibility to examine the stochastic behavior and the microscopic chemical reaction rates of these channel proteins in their natural environment. Such an analysis can yield detailed information about the molecular function that cannot be derived from recordings obtained from an ensemble of channels. In this review, we summarize experimental evidence suggesting that Ca2+ sparks, elementary Ca2+ signaling events of cardiac and skeletal muscle excitation contraction coupling, may be comprised of a number of smaller Ca2+ signaling events, the Ca2+ quarks.