Distinct types of astroglial cells in the hippocampus differ in gap junction coupling

Wallraff, Anke; Odermatt, Benjamin; Willecke, Klaus; Steinhäuser, Christian

doi:10.1002/glia.20040

Cited by 181 publications

(189 citation statements)

References 31 publications

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“…To clarify whether RG-like cells express Cx43, we used a transgenic approach. Cx43 fl/ϩ /hGFAP-Cre/hGFAP-EGFP mice (p90) were generated expressing ␤-galactosidase (␤-Gal) under control of regulatory elements of the Cx43 gene in hGFAP-Crepositive cells (17), allowing indirect analysis of Cx43 expression in hGFAP-EGFP-positive cells (Fig. S4).…”

Section: Resultsmentioning

confidence: 99%

Connexin expression by radial glia-like cells is required for neurogenesis in the adult dentate gyrus

Kunze

Congreso

Hartmann

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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124

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Section: Resultsmentioning

confidence: 99%

Connexin expression by radial glia-like cells is required for neurogenesis in the adult dentate gyrus

Kunze

Congreso

Hartmann

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

124

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“…These findings indicate that, in this brain region characterized by a strong anatomofunctional neuronal compartmentalization, astrocytes also exhibited a specific spatial organization and are constituted by several subpopulations with distinct coupling properties favoring intercellular communication within the barrel rather than between two neighboring barrels. In the septa, uncoupled astrocytes exhibit passive electrophysiological properties suggesting that in the somatosensory cortex, in contrast to the hippocampus (Matthias et al, 2003;Wallraff et al, 2004, there are subpopulations of PAs with different coupling properties.…”

Section: Discussionmentioning

confidence: 99%

“…Indeed, in many brain regions and throughout animal life, gap junctional communication (GJC) is extensive and widespread between subpopulations of astrocytes (D'Ambrosio et al, 1998;Blomstrand et al, 2004;Wallraff et al, 2004). Such communicating pathways are provided by junctional proteins named connexins (Cxs), members of a multigenic family (Theis et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Previous reports have demonstrated that GJC studied in astrocytes does not involve all astrocytes and that subpopulations of glial cells with a specific phenotype are not coupled (Wallraff et al, 2004;Houades et al, 2006;Schools et al, 2006). Accordingly, the initially proposed syncytium-like organization of glia (Mugnaini, 1986), suggesting that all glial cells communicate, has to be revised and the term of communicating networks seems to be more appropriate for astrocytes.…”

Section: Introductionmentioning

confidence: 99%

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Gap Junction-Mediated Astrocytic Networks in the Mouse Barrel Cortex

Houades¹,

Koulakoff²,

Ezan³

et al. 2008

J. Neurosci.

193

161

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The barrel field of the somatosensory cortex constitutes a well documented example of anatomofunctional compartmentalization and activity-dependent interaction between neurons and astrocytes. In astrocytes, intercellular communication through gap junction channels composed by connexin 43 and 30 underlies a network organization. Immunohistochemical and electrophysiological experiments were undertaken to determine the coupling properties of astrocyte networks in layer IV of the developing barrel cortex. The expression of both connexins was found to be enriched within barrels compared with septa and other cortical layers. Combination of dye-coupling experiments performed with biocytin and immunostaining with specific cell markers demonstrated that astrocytic networks do not involve neurons, oligodendrocytes or NG2 cells. The shape of dye coupling was oval in the barrel cortex whereas it was circular in layer IV outside the barrel field. Two-dimensional analysis of these coupling areas indicated that gap junctional communication was restricted from a barrel to its neighbor. Such enrichment of connexin expression and transversal restriction were not observed in a transgenic mouse lacking the barrel organization, whereas they were both observed in a double-transgenic mouse with restored barrels. Direct observation of sulforhodamine B spread indicated that astrocytes located between two barrels were either weakly or not coupled, whereas coupling within a barrel was oriented toward its center. These observations indicated a preferential orientation of coupling inside the barrels resulting from subpopulations of astrocytes with different coupling properties that contribute to shaping astrocytic networks. Such properties confine intercellular communication in astrocytes within a defined barrel as previously reported for excitatory neuronal circuits.

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“…The GluR cells completely lack gap junction coupling, whereas the GluT cells are extensively coupled. 75 Electron microscopic studies have identified synapse-like structures onto GluR cells and receive spontaneous synaptic inputs from GABAergic and glutamatergic neurons in acute hippocampal slice preparations. 76 The GluR cell described previously also closely resembles a cell type identified as a third class of macroglia and variously named as neuron glia-2 (NG2) cells, oligodendrocyte precursor cells, polydendrocytes, synantocyte, or complex cells.…”

Section: Astrocyte Typesmentioning

confidence: 99%

Astrocytes and Epilepsy

2010

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Summary: Astrocytes form a significant constituent of seizure foci in the human brain. For a long time it was believed that astrocytes play a significant role in the causation of seizures. With the increase in our understanding of the unique biology of these cells, their precise role in seizure foci is receiving renewed attention. This article reviews the information now available on the role of astrocytes in the hippocampal seizure focus in patients with temporal lobe epilepsy with hippocampal sclerosis. Our intent is to try to integrate the available data. Astrocytes at seizure foci seem to not be a homogeneous population of cells, and in addition to typical glial fibrillary acidic protein, positive reactive astrocytes also include a population of neuron glia-2-like cells The astrocytes in sclerotic hippocampi differ from those in nonsclerotic hippocampi in their membrane physiology, having elevated Naϩ channels and reduced inwardly rectifying potassium ion channels, and some having the capacity to generate action potentials. They also have reduced glutamine synthetase and increased glutamate dehydrogenase activity. The molecular interface between the astrocyte and microvasculature is also changed. The astrocytes are also associated with increased expression of many molecules normally concerned with immune and inflammatory functions. A speculative mechanism postulates that neuron glia-2-like cells may be involved in creating a high glutamate environment, whereas the function of more typical reactive astrocytes contribute to maintain high extracellular Kϩ levels; both factors contributing to the hyperexcitability of subicular neurons to generate epileptiform activity. The functions of the astrocyte vascular interface may be more critical to the processes involved in epileptogenesis.

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Distinct types of astroglial cells in the hippocampus differ in gap junction coupling

Cited by 181 publications

References 31 publications

Connexin expression by radial glia-like cells is required for neurogenesis in the adult dentate gyrus

Connexin expression by radial glia-like cells is required for neurogenesis in the adult dentate gyrus

Gap Junction-Mediated Astrocytic Networks in the Mouse Barrel Cortex

Astrocytes and Epilepsy

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