title: Connexin expression in homotypic and heterotypic cell coupling in the developing cerebral cortex.
abstract: Intercellular communication through gap junction channels is a prominent feature of the developing cerebral cortex. In the first 2 weeks after birth, a time critical in the development of the rat neocortex, extensive cell coupling has been documented that diminishes as the cortex matures. Among the family of gap junction proteins, connexins 26, 36, and 43 are differentially expressed during cortical development. We used intracellular dye injections and connexin immunohistochemistry to investigate the coupling patterns and connexin expression between the different neuronal and glial cell types of the developing cortex of the rat. We found that neurons and glia couple homotypically and heterotypically at postnatal days 7 and 14. Although the prevalence of coupling was homotypic, there was considerable heterotypic coupling that involved pyramidal and nonpyramidal neurons, the principal neuronal cell types of the cortex, or neurons and astrocytes. Coupling between different cell types appeared to be mediated by differential expression of connexins 26, 36, and 43. It may be that coupling between cells in the developing neocortex is a function of the spatial and temporal expression of these and other connexin proteins.
authors.affiliation: Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, United Kingdom.
authors.forename: Kevin
authors.initials: K
authors.lastname: Bittman
authors.forename: David L
authors.initials: DL
authors.lastname: Becker
authors.forename: Federico
authors.initials: F
authors.lastname: Cicirata
authors.forename: John G
authors.initials: JG
authors.lastname: Parnavelas
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism; D001369:Axons / Q000378:metabolism / Q000648:ultrastructure; D001710:Biotin / Q000031:analogs & derivatives*; D002450:Cell Communication / Q000502:physiology*; D048429:Cell Size / Q000502:physiology; D002540:Cerebral Cortex / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D000072259:Connexin 26; D018031:Connexin 43 / Q000378:metabolism; D017630:Connexins / Q000378:metabolism*; D003712:Dendrites / Q000378:metabolism / Q000648:ultrastructure; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D017629:Gap Junctions / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007150:Immunohistochemistry; D007395:Interneurons / Q000166:cytology / Q000378:metabolism; D018613:Microscopy, Confocal; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D017966:Pyramidal Cells / Q000166:cytology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000097004:Gap Junction delta-2 Protein
chemical_list: D001710:Biotin; D000072259:Connexin 26; D018031:Connexin 43; D017630:Connexins; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D000097004:Gap Junction delta-2 Protein; C070614:neurobiotin