chapter  5
18 Pages

- Neuroglial Networks: Glial Wiring Also Matters

When applied to glial cells, the difference between these two de¡nitions illustrates the conceptual changes that have been operated during the last three decades to account for their property of intercellular communication. Indeed, the presence of a large number of gap junctions has led to the proposal that glia are organized as a syncytium (Mugnaini 1986; see also Theis et al. 2005), and so far many works relative

5.1 Introduction .................................................................................................. 139 5.2 Glial Networks Rather Than a Panglial Syncytium ..................................... 140 5.3 Astroglial Networks Have Their Own Rules of Organization ..................... 141 5.4 Re¢exive Gap Junctions Provide a Subcellular Networking ........................ 142 5.5 Astroglial Networks Are under Control ....................................................... 143 5.6 A Network or Several Networks? ................................................................. 143 5.7 Metabolic Networks Contribute to Dynamic Neuroglial Interaction ........... 145 5.8 What Is the Contribution for Connexin-Mediated Astroglial

Networks to the Propagation of Intercellular Waves? .................................. 145 5.9 Other Roles from Astroglial Networks ......................................................... 146

5.9.1 Potassium Dissipation ....................................................................... 146 5.9.2 Masking of Pharmacological and Biochemical Heterogeneity ........ 147 5.9.3 Synapse and Neuroglial Networking ................................................ 148 5.9.4 Perivascular Astroglial Networks as Part of the

Gliovascular Unit .............................................................................. 149 5.10 Conclusions and Perspectives ....................................................................... 150 Acknowledgments .................................................................................................. 152 References .............................................................................................................. 152

to gap junctions in astrocytes refer to this syncytial concept. The purpose of this chapter is to update what is known about intercellular communication in astrocytes and their network organization in relation to dynamic interactions that astrocytes establish with neurons and the vascular system. These aspects have been recently presented in reviews (Giaume et al. 2010; Orellana et al. 2009); thus, in this chapter, I will place more emphasis on the potential roles of such astroglial networks and discuss future directions of research to better understand the role of astrocytes.