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Structure and function of gap junctions in the developing brain

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Gap-junction-dependent neuronal communication is widespread in the developing brain, and the prevalence of gap-junctional coupling is well correlated with specific developmental events. We summarize here our current knowledge of the contribution of gap junctions to brain development and propose that they carry out this role by taking advantage of the full complement of their functional properties. Thus, hemichannel activation may represent a key step in the initiation of Ca2+ waves that coordinate cell cycle events during early prenatal neurogenesis, whereas both hemichannels and/or gap junctions may control the division and migration of cohorts of precusor cells during late prenatal neurogenesis. Finally, the recent discovery that pannexins, a novel group of proteins prominently expressed in the brain, are able to form both hemichannels and gap-junction channels suggests that we need to seek more than just connexins with respect to these junctions.

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  1. Arumugam H, Liu X, Colombo PJ, Corriveau RA, Belousov AB (2005) NMDA receptors regulate developmental gap junction uncoupling via CREB signaling. Nat Neurosci 8:1720–1726

  2. Bao L, Locovei S, Dahl G (2004) Pannexin membrane channels are mechanosensitive conduits for ATP. FEBS Lett 572:65–68

  3. Baranova A, Ivanov D, Petrash N, Pestova A, Skoblov M, Kelmanson I, Shagin D, Nazarenko S, Geraymovych E, Litvin O, Tiunova A, Born TL, Usman N, Staroverov D, Lukyanov S, Panchin Y (2004) The mammalian pannexin family is homologous to the invertebrate innexin gap junction proteins. Genomics 83:706–716

  4. Barbe MT, Monyer H, Bruzzone R (2006) Cell-cell communication beyond connexins: the pannexin channels. Physiology (Bethesda) 21:103–114

  5. Belluardo N, Mudo G, Trovato-Salinaro A, Le Gurun S, Charollais A, Serre-Beinier V, Amato G, Haefliger JA, Meda P, Condorelli DF (2000) Expression of connexin36 in the adult and developing rat brain. Brain Res 865:121–138

  6. Bennett MV, Zukin RS (2004) Electrical coupling and neuronal synchronization in the mammalian brain. Neuron 41:495–511

  7. Bennett MV, Barrio LC, Bargiello TA, Spray DC, Hertzberg E, Saez JC (1991) Gap junctions: new tools, new answers, new questions. Neuron 6:305–320

  8. Bennett MV, Contreras JE, Bukauskas FF, Saez JC (2003) New roles for astrocytes: gap junction hemichannels have something to communicate. Trends Neurosci 26:610–617

  9. Berthoud VM, Singh R, Minogue PJ, Ragsdale CW, Beyer EC (2004) Highly restricted pattern of connexin36 expression in chick somite development. Anat Embryol (Berl) 209:11–18

  10. Beyer EC (1993) Gap junctions. Int Rev Cytol 137C:1–37

  11. Bittman K, Owens DF, Kriegstein AR, LoTurco JJ (1997) Cell coupling and uncoupling in the ventricular zone of developing neocortex. J Neurosci 17:7037–7044

  12. Bittman KS, LoTurco JJ (1999) Differential regulation of connexin 26 and 43 in murine neocortical precursors. Cereb Cortex 9:188–195

  13. Bruzzone R, White TW, Paul DL (1996) Connections with connexins: the molecular basis of direct intercellular signaling. Eur J Biochem 238:1–27

  14. Bruzzone R, Hormuzdi SG, Barbe MT, Herb A, Monyer H (2003) Pannexins, a family of gap junction proteins expressed in brain. Proc Natl Acad Sci USA 100:13644—13649

  15. Bruzzone R, Barbe MT, Jakob NJ, Monyer H (2005) Pharmacological properties of homomeric and heteromeric pannexin hemichannels expressed in Xenopus oocytes. J Neurochem 92:1033–1043

  16. Bryant PJ, Fraser SE (1988) Wound healing, cell communication, and DNA synthesis during imaginal disc regeneration in Drosophila. Dev Biol 127:197–208

  17. Condorelli DF, Parenti R, Spinella F, Trovato Salinaro A, Belluardo N, Cardile V, Cicirata F (1998) Cloning of a new gap junction gene (Cx36) highly expressed in mammalian brain neurons. Eur J Neurosci 10:1202–1208

  18. Connors BW, Long MA (2004) Electrical synapses in the mammalian brain. Annu Rev Neurosci 27:393–418

  19. Connors BW, Benardo LS, Prince DA (1983) Coupling between neurons of the developing rat neocortex. J Neurosci 3:773–782

  20. Contreras JE, Saez JC, Bukauskas FF, Bennett MV (2003) Gating and regulation of connexin 43 (Cx43) hemichannels. Proc Natl Acad Sci USA 100:11388–11393

  21. Cotrina ML, Lin JH, Alves-Rodrigues A, Liu S, Li J, Azmi-Ghadimi H, Kang J, Naus CC, Nedergaard M (1998) Connexins regulate calcium signaling by controlling ATP release. Proc Natl Acad Sci USA 95:15735–15740

  22. Deans MR, Paul DL (2001) Mouse horizontal cells do not express connexin26 or connexin36. Cell Commun Adhes 8:361–366

  23. Dermietzel R, Spray DC (1993) Gap junctions in the brain: where, what type, how many and why? Trends Neurosci 16:186–192

  24. Dermietzel R, Yancey SB, Traub O, Willecke K, Revel JP (1987) Major loss of the 28-kD protein of gap junction in proliferating hepatocytes. J Cell Biol 105:1925–1934

  25. Dermietzel R, Traub O, Hwang TK, Beyer E, Bennett MV, Spray DC, Willecke K (1989) Differential expression of three gap junction proteins in developing and mature brain tissues. Proc Natl Acad Sci USA 86:10148–10152

  26. Dermietzel R, Hertberg EL, Kessler JA, Spray DC (1991) Gap junctions between cultured astrocytes: immunocytochemical, molecular, and electrophysiological analysis. J Neurosci 11:1421–1432

  27. Dolmetsch RE, Xu K, Lewis RS (1998) Calcium oscillations increase the efficiency and specificity of gene expression. Nature 392:933–936

  28. Dong CJ, McReynolds JS (1991) The relationship between light, dopamine release and horizontal cell coupling in the mudpuppy retina. J Physiol (Lond) 440:291–309

  29. Dowling JE (1987) The retina: an approachable part of the brain. Belknap, Cambridge, Mass

  30. Draguhn A, Traub RD, Schmitz D, Jefferys JG (1998) Electrical coupling underlies high-frequency oscillations in the hippocampus in vitro. Nature 394:189–192

  31. Duval N, Gomes D, Calaora V, Calabrese A, Meda P, Bruzzone R (2002) Cell coupling and Cx43 expression in embryonic mouse neural progenitor cells. J Cell Sci 115:3241–3251

  32. Ebihara L (2003) New roles for connexons. News Physiol Sci 18:100–103

  33. Ewart JL, Cohen MF, Meyer RA, Huang GY, Wessels A, Gourdie RG, Chin AJ, Park SM, Lazatin BO, Villabon S, Lo CW (1997) Heart and neural tube defects in transgenic mice overexpressing the Cx43 gap junction gene. Development 124:1281–1292

  34. Filippov MA, Hormuzdi SG, Fuchs EC, Monyer H (2003) A reporter allele for investigating connexin 26 gene expression in the mouse brain. Eur J Neurosci 18:3183–3192

  35. Fraser SE, Bryant PJ (1985) Patterns of dye coupling in the imaginal wing disk of Drosophila melanogaster. Nature 317:533–536

  36. Fushiki S, Perez Velazquez JL, Zhang L, Bechberger JF, Carlen PL, Naus CC (2003) Changes in neuronal migration in neocortex of connexin43 null mutant mice. J Neuropathol Exp Neurol 62:304–314

  37. Gellhaus A, Dong X, Propson S, Maass K, Klein-Hitpass L, Kibschull M, Traub O, Willecke K, Perbal B, Lye SJ, Winterhager E (2004) Connexin43 interacts with NOV: a possible mechanism for negative regulation of cell growth in choriocarcinoma cells. J Biol Chem 279:36931–36942

  38. Giaume C, Fromaget C, el Aoumari A, Cordier J, Glowinski J, Gros D (1991) Gap junctions in cultured astrocytes: single-channel currents and characterization of channel-forming protein. Neuron 6:133–143

  39. Goodenough DA, Paul DL (2003) Beyond the gap: functions of unpaired connexon channels. Nat Rev Mol Cell Biol 4:285–294

  40. Goodman CS, Spitzer NC (1981) The development of electrical properties of identified neurones in grasshopper embryos. J Physiol (Lond) 313:385–403

  41. Green J (2002) Morphogen gradients, positional information, and Xenopus: interplay of theory and experiment. Dev Dyn 225:392–408

  42. Gulisano M, Parenti R, Spinella F, Cicirata F (2000) Cx36 is dynamically expressed during early development of mouse brain and nervous system. Neuroreport 11:3823–3828

  43. Harris AL (2001) Emerging issues of connexin channels: biophysics fills the gap. Q Rev Biophys 34:325–472

  44. Hofer A, Dermietzel R (1998) Visualization and functional blocking of gap junction hemichannels (connexons) with antibodies against external loop domains in astrocytes. Glia 24:141–154

  45. Hormuzdi SG, Pais I, LeBeau FE, Towers SK, Rozov A, Buhl EH, Whittington MA, Monyer H (2001) Impaired electrical signaling disrupts gamma frequency oscillations in connexin 36-deficient mice. Neuron 31:487–495

  46. Hormuzdi SG, Filippov MA, Mitropoulou G, Monyer H, Bruzzone R (2004) Electrical synapses: a dynamic signaling system that shapes the activity of neuronal networks. Biochim Biophys Acta 1662:113–137

  47. Huang GY, Cooper ES, Waldo K, Kirby ML, Gilula NB, Lo CW (1998a) Gap junction-mediated cell-cell communication modulates mouse neural crest migration. J Cell Biol 143:1725–1734

  48. Huang GY, Wessels A, Smith BR, Linask KK, Ewart JL, Lo CW (1998b) Alteration in connexin 43 gap junction gene dosage impairs conotruncal heart development. Dev Biol 198:32–44

  49. Jungbluth S, Willecke K, Champagnat J (2002) Segment-specific expression of connexin31 in the embryonic hindbrain is regulated by Krox20. Dev Dyn 223:544–551

  50. Jursnich VA, Fraser SE, Held LI Jr, Ryerse J, Bryant PJ (1990) Defective gap-junctional communication associated with imaginal disc overgrowth and degeneration caused by mutations of the dco gene in Drosophila. Dev Biol 140:413–429

  51. Kandler K, Katz LC (1995) Neuronal coupling and uncoupling in the developing nervous system. Curr Opin Neurobiol 5:98–105

  52. Kandler K, Katz LC (1998a) Relationship between dye coupling and spontaneous activity in developing ferret visual cortex. Dev Neurosci 20:59–64

  53. Kandler K, Katz LC (1998b) Coordination of neuronal activity in developing visual cortex by gap junction-mediated biochemical communication. J Neurosci 18:1419–1427

  54. Kandler K, Thiels E (2005) Flipping the switch from electrical to chemical communication. Nat Neurosci 8:1633–1634

  55. Katz LC (1995) Coordination of vertebrate cellular assemblies by gap junctions. Semin Dev Biol 6:117–125

  56. Leung DS, Unsicker K, Reuss B (2002) Expression and developmental regulation of gap junction connexins Cx26, Cx32, Cx43 and Cx45 in the rat midbrain-floor. Int J Dev Neurosci 20:63–75

  57. Li H, Liu TF, Lazrak A, Peracchia C, Goldberg GS, Lampe PD, Johnson RG (1996) Properties and regulation of gap junctional hemichannels in the plasma membranes of cultured cells. J Cell Biol 134:1019–1030

  58. Li W, Llopis J, Whitney M, Zlokarnik G, Tsien RY (1998) Cell-permeant caged InsP3 ester shows that Ca2+ spike frequency can optimize gene expression. Nature 392:936–941

  59. Lo CW, Waldo KL, Kirby ML (1999) Gap junction communication and the modulation of cardiac neural crest cells. Trends Cardiovasc Med 9:63–69

  60. Lo Turco JJ, Kriegstein AR (1991) Clusters of coupled neuroblasts in embryonic neocortex. Science 252:563–566

  61. Locovei S, Wang J, Dahl G (2006a) Activation of pannexin 1 channels by ATP through P2Y receptors and by cytoplasmic calcium. FEBS Lett 580:239–244

  62. Locovei S, Bao L, Dahl G (2006b) Pannexin 1 in erythrocytes: function without a gap. Proc Natl Acad Sci USA 103:7655–7659

  63. Martin AO, Mathieu MN, Chevillard C, Guerineau NC (2001) Gap junctions mediate electrical signaling and ensuing cytosolic Ca2+ increases between chromaffin cells in adrenal slices: a role in catecholamine release. J Neurosci 21:5397–5405

  64. Maxeiner S, Kruger O, Schilling K, Traub O, Urschel S, Willecke K (2003) Spatiotemporal transcription of connexin45 during brain development results in neuronal expression in adult mice. Neuroscience 119:689–700

  65. Meyer AH, Katona I, Blatow M, Rozov A, Monyer H (2002) In vivo labeling of parvalbumin-positive interneurons and analysis of electrical coupling in identified neurons. J Neurosci 22:7055–7064

  66. Mills SL, Massey SC (1995) Differential properties of two gap junctional pathways made by AII amacrine cells. Nature 377:734–737

  67. Miragall F, Albiez P, Bartels H, Vries U de, Dermietzel R (1997) Expression of the gap junction protein connexin43 in the subependymal layer and the rostral migratory stream of the mouse: evidence for an inverse correlation between intensity of connexin43 expression and cell proliferation activity. Cell Tissue Res 287:243–253

  68. Nadarajah B, Jones AM, Evans WH, Parnavelas JG (1997) Differential expression of connexins during neocortical development and neuronal circuit formation. J Neurosci 17:3096–3111

  69. Nadarajah B, Makarenkova H, Becker DL, Evans WH, Parnavelas JG (1998) Basic FGF increases communication between cells of the developing neocortex. J Neurosci 18:7881–7890

  70. Nagy JI, Ionescu AV, Lynn BD, Rash JE (2003) Coupling of astrocyte connexins Cx26, Cx30, Cx43 to oligodendrocyte Cx29, Cx32, Cx47: implications from normal and connexin32 knockout mice. Glia 44:205–218

  71. Nagy JI, Dudek FE, Rash JE (2004) Update on connexins and gap junctions in neurons and glia in the mammalian nervous system. Brain Res Brain Res Rev 47:191–215

  72. Nakase T, Naus CC (2004) Gap junctions and neurological disorders of the central nervous system. Biochim Biophys Acta 1662:149–158

  73. Nicholson BJ, Weber PA, Cao F, Chang H, Lampe P, Goldberg G (2000) The molecular basis of selective permeability of connexins is complex and includes both size and charge. Braz J Med Biol Res 33:369–378

  74. Okada H, Miyakawa N, Mori H, Mishina M, Miyamoto Y, Hisatsune T (2003) NMDA receptors in cortical development are essential for the generation of coordinated increases in [Ca2+](i) in “neuronal domain”. Cereb Cortex 13:749–757

  75. Owens DF, Kriegstein AR (1998) Patterns of intracellular calcium fluctuation in precursor cells of the neocortical ventricular zone. J Neurosci 18:5374–5388

  76. Panchin Y, Kelmanson I, Matz M, Lukyanov K, Usman N, Lukyanov S (2000) A ubiquitous family of putative gap junction molecules. Curr Biol 10:R473–R474

  77. Paul DL, Ebihara L, Takemoto LJ, Swenson KI, Goodenough DA (1991) Connexin46, a novel lens gap junction protein, induces voltage-gated currents in nonjunctional plasma membrane of Xenopus oocytes. J Cell Biol 115:1077–1089

  78. Pearson RA, Dale N, Llaudet E, Mobbs P (2005) ATP released via gap junction hemichannels from the pigment epithelium regulates neural retinal progenitor proliferation. Neuron 46:731–744

  79. Peinado A, Yuste R, Katz LC (1993a) Gap junctional communication and the development of local circuits in neocortex. Cereb Cortex 3:488–498

  80. Peinado A, Yuste R, Katz LC (1993b) Extensive dye coupling between rat neocortical neurons during the period of circuit formation. Neuron 10:103–114

  81. Pfahnl A, Dahl G (1999) Gating of Cx46 gap junction hemichannels by calcium and voltage. Pflügers Arch 437:345–353

  82. Piccolino M, Neyton J, Gerschenfeld HM (1984) Decrease of gap junction permeability induced by dopamine and cyclic adenosine 3′:5′-monophosphate in horizontal cells of turtle retina. J Neurosci 4:2477–2488

  83. Ray A, Zoidl G, Weickert S, Wahle P, Dermietzel R (2005) Site-specific and developmental expression of pannexin1 in the mouse nervous system. Eur J Neurosci 21:3277–3290

  84. Reaume AG, Sousa PA de, Kulkarni S, Langille BL, Zhu D, Davies TC, Juneja SC, Kidder GM, Rossant J (1995) Cardiac malformation in neonatal mice lacking connexin43. Science 267:1831–1834

  85. Rörig B, Sutor B (1996) Serotonin regulates gap junction coupling in the developing rat somatosensory cortex. Eur J Neurosci 8:1685–1695

  86. Rörig B, Feller MB (2000) Neurotransmitters and gap junctions in developing neural circuits. Brain Res Brain Res Rev 32:86–114

  87. Rörig B, Klausa G, Sutor B (1995) Beta-adrenoreceptor activation reduces dye-coupling between immature rat neocortical neurones. Neuroreport 6:1811–1815

  88. Rozental R, Mehler MF, Morales M, Andrade-Rozental AF, Kessler JA, Spray DC (1995) Differentiation of hippocampal progenitor cells in vitro: temporal expression of intercellular coupling and voltage- and ligand-gated responses. Dev Biol 167:350–362

  89. Rozental R, Morales M, Mehler MF, Urban M, Kremer M, Dermietzel R, Kessler JA, Spray DC (1998) Changes in the properties of gap junctions during neuronal differentiation of hippocampal progenitor cells. J Neurosci 18:1753–1762

  90. Sasakura Y, Shoguchi E, Takatori N, Wada S, Meinertzhagen IA, Satou Y, Satoh N (2003) A genomewide survey of developmentally relevant genes in Ciona intestinalis. X. Genes for cell junctions and extracellular matrix. Dev Genes Evol 213:303–313

  91. Scherer SS, Deschenes SM, Xu YT, Grinspan JB, Fischbeck KH, Paul DL (1995) Connexin32 is a myelin-related protein in the PNS and CNS. J Neurosci 15:8281–8294

  92. Serre-Beinier V, Le Gurun S, Belluardo N, Trovato-Salinaro A, Charollais A, Haefliger JA, Condorelli DF, Meda P (2000) Cx36 preferentially connects beta-cells within pancreatic islets. Diabetes 49:727–734

  93. Sohl G, Degen J, Teubner B, Willecke K (1998) The murine gap junction gene connexin36 is highly expressed in mouse retina and regulated during brain development. FEBS Lett 428:27–31

  94. Sohl G, Odermatt B, Maxeiner S, Degen J, Willecke K (2004) New insights into the expression and function of neural connexins with transgenic mouse mutants. Brain Res Brain Res Rev 47:245–259

  95. Sohl G, Maxeiner S, Willecke K (2005) Expression and functions of neuronal gap junctions. Nat Rev Neurosci 6:191–200

  96. Sosinsky GE, Nicholson BJ (2005) Structural organization of gap junction channels. Biochim Biophys Acta 1711:99–125

  97. Spitzer NC (1991) A developmental handshake: neuronal control of ionic currents and their control of neuronal differentiation. J Neurobiol 22:659–673

  98. Theis M, Sohl G, Eiberger J, Willecke K (2005) Emerging complexities in identity and function of glial connexins. Trends Neurosci 28:188–195

  99. Thompson RJ, Zhou N, MacVicar BA (2006) Ischemia opens neuronal gap junction hemichannels. Science 312:924–927

  100. Traub O, Hertlein B, Kasper M, Eckert R, Krisciukaitis A, Hulser D, Willecke K (1998) Characterization of the gap junction protein connexin37 in murine endothelium, respiratory epithelium, and after transfection in human HeLa cells. Eur J Cell Biol 77:313–322

  101. Traub RD, Michelson-Law H, Bibbig AE, Buhl EH, Whittington MA (2004a) Gap junctions, fast oscillations and the initiation of seizures. Adv Exp Med Biol 548:110–122

  102. Traub RD, Bibbig A, LeBeau FE, Buhl EH, Whittington MA (2004b) Cellular mechanisms of neuronal population oscillations in the hippocampus in vitro. Annu Rev Neurosci 27:247–278

  103. Trexler EB, Bennett MV, Bargiello TA, Verselis VK (1996) Voltage gating and permeation in a gap junction hemichannel. Proc Natl Acad Sci USA 93:5836–5841

  104. Tsien RY (1992) Intracellular signal transduction in four dimensions: from molecular design to physiology. Am J Physiol 263:C723–C728

  105. Veenstra RD (1996) Size and selectivity of gap junction channels formed from different connexins. J Bioenerg Biomembr 28:327–337

  106. Venance L, Rozov A, Blatow M, Burnashev N, Feldmeyer D, Monyer H (2000) Connexin expression in electrically coupled postnatal rat brain neurons. Proc Natl Acad Sci USA 97:10260–10265

  107. Vogt A, Hormuzdi SG, Monyer H (2005) Pannexin1 and pannexin2 expression in the developing and mature rat brain. Brain Res Mol Brain Res 141:113–120

  108. Warner A (1992) Gap junctions in development—a perspective. Semin Cell Biol 3:81–91

  109. Warner AE (1985) The role of gap junctions in amphibian development. J Embryol Exp Morphol 89(Suppl):365–380

  110. Wei CJ, Xu X, Lo CW (2004) Connexins and cell signaling in development and disease. Annu Rev Cell Dev Biol 20:811–838

  111. Weickert S, Ray A, Zoidl G, Dermietzel R (2005) Expression of neural connexins and pannexin1 in the hippocampus and inferior olive: a quantitative approach. Brain Res Mol Brain Res 133:102–109

  112. Weiler R, Pottek M, He S, Vaney DI (2000) Modulation of coupling between retinal horizontal cells by retinoic acid and endogenous dopamine. Brain Res Brain Res Rev 32:121–129

  113. Weissman TA, Riquelme PA, Ivic L, Flint AC, Kriegstein AR (2004) Calcium waves propagate through radial glial cells and modulate proliferation in the developing neocortex. Neuron 43:647–661

  114. White TW, Deans MR, O'Brien J, Al-Ubaidi MR, Goodenough DA, Ripps H, Bruzzone R (1999) Functional characteristics of skate connexin35, a member of the gamma subfamily of connexins expressed in the vertebrate retina. Eur J Neurosci 11:1883–1890

  115. Whittington MA, Traub RD (2003) Interneuron diversity series: inhibitory interneurons and network oscillations in vitro. Trends Neurosci 26:676–682

  116. Wolpert L (1969) Positional information and the spatial pattern of cellular differentiation. J Theor Biol 25:1–47

  117. Wolpert L (1989) Positional information revisited. Development 107(Suppl):3–12

  118. Ye ZC, Wyeth MS, Baltan-Tekkok S, Ransom BR (2003) Functional hemichannels in astrocytes: a novel mechanism of glutamate release. J Neurosci 23:3588–3596

  119. Yuste R, Peinado A, Katz LC (1992) Neuronal domains in developing neocortex. Science 257:665–669

  120. Yuste R, Nelson DA, Rubin WW, Katz LC (1995) Neuronal domains in developing neocortex: mechanisms of coactivation. Neuron 14:7–17

  121. Zappala A, Cicero D, Serapide MF, Paz C, Catania MV, Falchi M, Parenti R, Panto MR, La Delia F, Cicirata F (2006) Expression of pannexin1 in the CNS of adult mouse: cellular localization and effect of 4-aminopyridine-induced seizures. Neuroscience (in press)

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Correspondence to Rolf Dermietzel.

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Work in the authors’ laboratories is supported by the Deutsche Forschungsgemeinschaft, SFB 509 (R.D.) and by the Institut Pasteur (R.B.).

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Bruzzone, R., Dermietzel, R. Structure and function of gap junctions in the developing brain. Cell Tissue Res 326, 239–248 (2006). https://doi.org/10.1007/s00441-006-0287-0

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  • Gap junction
  • Brain development
  • Prenatal neurogenesis
  • Pannexins
  • Hemichannels