Plasticity of astroglial networks in olfactory glomeruli

Lisa Roux, Karim Benchenane, Jeffrey D. Rothstein, Gilles Bonvento, Christian Giaume

Research output: Contribution to journalArticlepeer-review

Abstract

Several recent findings have shown that neurons as well as astrocytes are organized into networks. Indeed, astrocytes are interconnected through connexin-formed gap junction channels allowing exchanges of ions and signaling molecules. The aim of this study is to characterize astrocyte network properties in mouse olfactory glomeruli where neuronal connectivity is highly ordered. Dyecoupling experiments performed in olfactory bulb acute slices (P16-P22) highlight a preferential communication between astrocytes within glomeruli and not between astrocytes in adjacent glomeruli. Such organization relies on the oriented morphology of glomerular astrocytes to the glomerulus center and the enriched expression of two astroglial connexins (Cx43 and Cx30) within the glomeruli. Glomerular astrocytes detect neuronal activity showing membrane potential fluctuations correlated with glomerular local field potentials. Accordingly, gap junctional coupling of glomerular networks is reduced when neuronal activity is silenced by TTX treatment or after early sensory deprivation. Such modulation is lost in Cx30 but not in Cx43 KO mice, indicating that Cx30-formed channels are the molecular targets of this activity-dependent modulation. Extracellular potassiumis a key player in this neuroglial interaction, because (i) the inhibition of dye coupling observed in the presence of TTX or after sensory deprivation is restored by increasing [K +] eand (ii) treatment with a K ir channel blocker inhibits dye spread between glomerular astrocytes. Together, these results demonstrate that extracellular potassium generated by neuronal activity modulates Cx30-mediated gap junctional communication between glomerular astrocytes, indicating that strong neuroglial interactions take place at this first relay of olfactory information processing.

Original languageEnglish (US)
Pages (from-to)18442-18446
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number45
DOIs
StatePublished - Nov 8 2011

Keywords

  • Functional unit
  • Glia
  • Naris occlusion

ASJC Scopus subject areas

  • General

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