J Physiol Volume 583, Number 3, 945-958, September 15, 2007 DOI: 10.1113/jphysiol.2007.135715
Bioluminescent imaging of Ca2+ activity reveals spatiotemporal dynamics in glial networks of dark-adapted mouse retina
Cendra Agulhon1,
Jean-Claude Platel3,
Bogdan Kolomiets5,6,7,
Valérie Forster5,6,
Serge Picaud5,6,7,
Jacques Brocard4,
Philippe Faure2 and
Philippe Brulet1
1 Unité d'Embryologie Moléculaire, CNRS URA 2578
2 Unité de Neurobiologie Intégrative des Systémes Cholinergiques Institut Pasteur, 25–28 rue du Docteur Roux, 75724 Paris Cedex, France
3 INSERM U704, Dynamique des Réseaux Neuronaux, Grenoble, F-38041, France
4 INSERM U366, Laboratoire du Cytosquelette, Grenoble F-38054, France
5 INSERM U592, Laboratoire de Physiopathologie Cellulaire et Moléculaire de la Rétine, Paris, France
6 Université Pierre et Marie Curie-Paris 6, UMR S592, F-75012 Paris, France
7 Fondation Ophtalmologique A. de Rothschild, F-75012 Paris, France
Glial Ca2+ excitability plays a key role in reciprocal neuron–glia communication. In the retina, neuron–glia signalling is expected to be maximal in the dark, but the glial Ca2+ signal characteristics under such conditions have not been evaluated. To address this question, we used bioluminescence imaging to monitor spontaneous Ca2+ changes under dark conditions selectively in Müller cells, the principal retinal glial cells. By combining this imaging approach with network analysis, we demonstrate that activity in Müller cells is organized in networks of coactive cells, involving 2–16 cells located distantly and/or in clusters. We also report that spontaneous activity of small networks (2–6 Müller cells) repeat over time, sometimes in the same sequential order, revealing specific temporal dynamics. In addition, we show that networks of coactive glial cells are inhibited by TTX, indicating that ganglion and/or amacrine neuronal cells probably regulate Müller cell network properties. These results represent the first demonstration that spontaneous activity in adult Müller cells is patterned into correlated networks that display repeated sequences of coactivations over time. Furthermore, our bioluminescence technique provides a novel tool to study the dynamic characteristics of glial Ca2+ events in the retina under dark conditions, which should greatly facilitate future investigations of retinal dark-adaptive processes.
(Received 1 May 2007;
accepted after revision 6 July 2007;
first published online 12 July 2007)
Corresponding author C. Agulhon: Department of Pharmacology, 1004 Mary Ellen Jones Building, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7365, USA. Email: cendra_agulhon{at}med.unc.edu
This paper has online supplemental material.
Copyright © 2007 The Physiological Society.
