title: Spatial properties of astrocyte gap junction coupling in the rat hippocampus.
abstract: Gap junction coupling enables astrocytes to form large networks. Its strength determines how easily a signalling molecule diffuses through the network and how far a locally initiated signal can spread. Changes of coupling strength are well-documented during development and in response to various stimuli. Precise quantification of coupling is needed for studying such modifications and their functional consequences. We therefore explored spatial properties of astrocyte coupling in a model simulating dye loading of single astrocytes. Dye spread into the astrocyte network could be characterized by a coupling length constant and coupling anisotropy. In experiments, the fluorescent marker Alexa Fluor 594 was used to measure these parameters in CA1 and dentate gyrus of the rat hippocampus. Coupling did not differ between regions but showed a temperature-dependence, partially owing to changes of intracellular diffusivity, detected by measuring coupling length constants but not the more variable cell counts of dye-coupled astrocytes. We further found that coupling is anisotropic depending on distance to the pyramidal cell layer, which correlated with regional differences of astrocyte morphology. This demonstrates that applying these new analytical approaches provides useful quantitative information on gap junction coupling and its heterogeneity.
authors.affiliation: Institute of Cellular Neurosciences, Medical School, University of Bonn, Bonn, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Anders
authors.affiliation: Institute of Cellular Neurosciences, Medical School, University of Bonn, Bonn, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Minge
authors.affiliation: Institute of Cellular Neurosciences, Medical School, University of Bonn, Bonn, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Griemsmann
authors.affiliation: Institute of Cellular Neurosciences, Medical School, University of Bonn, Bonn, Germany.
authors.forename: Michel K
authors.initials: MK
authors.lastname: Herde
authors.affiliation: Institute of Cellular Neurosciences, Medical School, University of Bonn, Bonn, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Steinhäuser
authors.affiliation: Institute of Cellular Neurosciences, Medical School, University of Bonn, Bonn, Germany UCL Institute of Neurology, UCL, London, UK christian.henneberger@ukb.uni-bonn.de.
authors.forename: Christian
authors.identifier: http://orcid.org/0000-0002-5391-7387
authors.initials: C
authors.lastname: Henneberger
mesh_terms: D000818:Animals; D016880:Anisotropy; D001253:Astrocytes / Q000648:ultrastructure*; D003198:Computer Simulation; D017629:Gap Junctions / Q000378:metabolism* / Q000648:ultrastructure*; D005904:Glial Fibrillary Acidic Protein; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology*; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods*; D008959:Models, Neurological; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009930:Organic Chemicals; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000502:physiology*; D013696:Temperature
chemical_list: C417664:Alexa594; D005904:Glial Fibrillary Acidic Protein; D009419:Nerve Tissue Proteins; D009930:Organic Chemicals; C485184:enhanced green fluorescent protein; C528900:glial fibrillary astrocytic protein, mouse; D049452:Green Fluorescent Proteins
keywords: astrocytes; dentate gyrus; gap junction coupling; hippocampus; spatial properties; temperature