title: Gray matter NG2 cells display multiple Ca2+-signaling pathways and highly motile processes.
abstract: NG2 cells, the fourth type of glia in the mammalian CNS, receive synaptic input from neurons. The function of this innervation is unknown yet. Postsynaptic changes in intracellular Ca(2+)-concentration ([Ca(2+)](i)) might be a possible consequence. We employed transgenic mice with fluorescently labeled NG2 cells to address this issue. To identify Ca(2+)-signaling pathways we combined patch-clamp recordings, Ca(2+)-imaging, mRNA-transcript analysis and focal pressure-application of various substances to identified NG2-cells in acute hippocampal slices. We show that activation of voltage-gated Ca(2+)-channels, Ca(2+)-permeable AMPA-receptors, and group I metabotropic glutamate-receptors provoke [Ca(2+)](i)-elevations in NG2 cells. The Ca(2+)-influx is amplified by Ca(2+)-induced Ca(2+)-release. Minimal electrical stimulation of presynaptic neurons caused postsynaptic currents but no somatic [Ca(2+)](i) elevations, suggesting that [Ca(2+)](i) elevations in NG2 cells might be restricted to their processes. Local Ca(2+)-signaling might provoke transmitter release or changes in cell motility. To identify structural prerequisites for such a scenario, we used electron microscopy, immunostaining, mRNA-transcript analysis, and time lapse imaging. We found that NG2 cells form symmetric and asymmetric synapses with presynaptic neurons and show immunoreactivity for vesicular glutamate transporter 1. The processes are actin-based, contain ezrin but not glial filaments, microtubules or endoplasmic reticulum. Furthermore, we demonstrate that NG2 cell processes in situ are highly motile. Our findings demonstrate that gray matter NG2 cells are endowed with the cellular machinery for two-way communication with neighboring cells.
authors: Institute of Cellular Neurosciences, University of Bonn, Bonn, Germany.
authors: Christian
authors: C
authors: Haberlandt
authors: Amin
authors: A
authors: Derouiche
authors: Alexandra
authors: A
authors: Wyczynski
authors: Julia
authors: J
authors: Haseleu
authors: Jörg
authors: J
authors: Pohle
authors: Khalad
authors: K
authors: Karram
authors: Jacqueline
authors: J
authors: Trotter
authors: Gerald
authors: G
authors: Seifert
authors: Michael
authors: M
authors: Frotscher
authors: Christian
authors: C
authors: Steinhäuser
authors: Ronald
authors: R
authors: Jabs
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004594:Electrophysiology; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D009457:Neuroglia / Q000378:metabolism* / Q000648:ultrastructure; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D050598:Vesicular Glutamate Transport Protein 1 / Q000378:metabolism
chemical_list: D050598:Vesicular Glutamate Transport Protein 1; D002118:Calcium