Chapter 8
Calcium Ion Signaling in Astrocytes
Joachim W. Deitmer, Karthika Singaravelu, and Christian Lohr
8.1 Introduction
Ca
2+
signaling has been recognized as one of the major second messenger steps in
most cell types, including astrocytes, the major macroglial cell type in vertebrate
nervous systems. Astrocytes are by no means a homogeneous group of glial cells,
but comprise a number of different cell types (see Chap. 1). However, in contrast to
a decade ago, when mammalian astrocytes were divided into either protoplasmic
type 1 or fibrous type II astrocytes, we assume today that there are many types of
astrocytes in different brain regions. Another classification has recognized astro-
cytes with a dense distribution of glutamate uptake transporters (EAAT, excitatory
amino acid transporter) and poor equipment of ionotropic glutamate receptors,
while another type of astrocytes shows a poor expression of EAATs, but prominent
distribution of ionotropic glutamate receptors. As with all of these cell type
V. Parpura and P.G. Haydon (eds.), Astrocytes in (Patho)Physiology of the Nervous System, 201
DOI: 10.1007/978-0-387-79492-1_8, © Springer Science + Business Media, LLC 2009
J.W. Deitmer
Abteilung für Allgemeine Zoologie, FB Biologie, TU Kaiserslautern, Kaiserslautern, Germany.
deitmer@biologie.uni-kl.de
Contents
8.1 Introduction ................................................................................................................... 201
8.2 Modes and Mechanisms of Ca
2+
Signaling ................................................................... 202
8.3 Spontaneous Ca
2+
Transients and Oscillations .............................................................. 206
8.4 Propagation of Ca
2+
Signals .......................................................................................... 208
8.5 Ca
2+
Responses to Transmitters and Other Signaling Molecules.................................. 210
8.6 Ca
2+
Responses to Neuronal Activity ............................................................................ 211
8.7 Store-Operated Ca
2+
Entry and Ca
2+
Store Refilling ..................................................... 213
8.8 Ca
2+
-Induced Release of Gliotransmitters..................................................................... 215
8.9 Functional Significance of Ca
2+
Signaling .................................................................... 216
8.10 Summary and Conclusion ............................................................................................. 217
References ................................................................................................................................ 218
Abbreviations ........................................................................................................................... 224