Bioluminescent imaging of Ca2+ activity reveals spatiotemporal dynamics in glial networks of dark-adapted mouse retina.
Glial Ca(2+) 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 Ca(2+) signal characteristics under such conditions have not been evaluated. To address this question, we used bioluminescence imaging to monitor spontaneous Ca(2+) 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 Ca(2+) events in the retina under dark conditions, which should greatly facilitate future investigations of retinal dark-adaptive processes.
Agulhon
Cendra
C
Unité d'Embryologie Moléculaire, CNRS URA 257, France. cendra_agulhon@med.unc.edu
Platel
Jean-Claude
JC
Kolomiets
Bogdan
B
Forster
Valérie
V
Picaud
Serge
S
Brocard
Jacques
J
Faure
Philippe
P
Brulet
Philippe
P
D000331:Aequorin / Q000235:genetics; D000367:Age Factors; D025042:Amacrine Cells / Q000166:cytology / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D003593:Cytoplasm / Q000502:physiology; D003623:Dark Adaptation / Q000502:physiology*; D017930:Genes, Reporter / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods*; D009457:Neuroglia / Q000502:physiology*; D012160:Retina / Q000166:cytology* / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000502:physiology
D049452:Green Fluorescent Proteins; D000331:Aequorin; D002118:Calcium