Table Of ContentNEUROSCIENCE
INTELLIGENCE
UNIT
GAP
}UNCTIONS
IN THE
NERVOUS SYSTEM
David C. Spray
Albert Einstein College of Medicine
Bronx, New York, U.S.A.
Rolf Dermietzel
University of Regensburg
Regensburg, Germany
Springer-Verlag
Berlin Heidelberg GmbH RG. LANDES CoMPANY
AUSTIN
NEUROSOENCE INTELIJGENCE UNIT
GAP JUNCTIONS IN THE NERVOUS SYSTEM
R.G. LANDES COMPANY
Austin, Texas, U.S.A.
International Copyright © 1996 Springer-Verlag Berlin Heidelberg
Originally published by Springer-Verlag, Heidelberg, Germany in 1996
Softcover reprint of the hardcover 1st edition 1996
All rights reserved.
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tronic or mechanical, including photocopy, recording, or any information storage and retrieval
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'Springer
ISBN 978-3-662-21937-9
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Library of Congress Cataloging-in-Publication Data
Gap junctions in the nervous system I [edited by] David C. Spray, Rolf Dermeitzel.
p. em. - (Neuroscience intelligence unit)
Includes bibliographical references and index.
ISBN 978-3-662-21937-9 ISBN 978-3-662-21935-5 (eBook)
DOI 10.1007/978-3-662-21935-5
1. Molecular neurobiology. 2. Connexins. 3. Cell junctions (Cell
biology) I. Spray, David C. II. Dermeitzel, Rolf. III. Series.
[DNLM: 1. Central Nervous System-physiology. 2. Gap Junctions
WL300 G211 1996
QP356.2.G37 1996
612.8-dc20
DNLM/DLC 96-28050
for Library of Congress CIP
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CONTENTS
r;:::=:====== ==========il
1. Gap Junctions in the Nervous System: An Introduction ............. 1
David C. Spray and RolfD ermietzel
1. Introduction ..................................................................................... 1
2. Connexin Brain Topology ................................................................ 2
3. Evolutionary Aspects of the Connexin Gene Family .......................... 4
4. Communication Compartments in the Nervous System ................... 5
5. Novel Approaches to Studying Gap Junctions ................................... 7
6. Organization of this Volume ............................................................. 8
2. Molecular Diversity and Plasticity of Gap Junctions
in the Nervous System .............................................................. 13
J?oljflJerr.nietzel
1. Introduction: An Evolutionary Perspective ...................................... 13
2. The Neural Compartment .............................................................. 14
3. Astrocytes Express a Complement of Class II (a) Connexins .......... 23
4. Myelinating Cells and the Presence of Reflexive Gap Junctions ....... 26
3. Physiological Properties of Gap Junction Channels
in the Nervous System .............................................................. 39
David C. Spray
1. Introduction ................................................................................... 39
2. Why Are There So Many Types of Gap Junctions? ......................... 40
4. Biophysical Properties of Gap Junction Channels ........................... 42
4. Gating Properties of Gap Junction Channels .................................. 44
5. Gating of Gap Junction Channels in Nervous Tissue ...................... 52
6. Conclusions .................................................................................... 54
4. Gap Junctions as Electrical Synapses ......................................... 61
Michael V. L. Bennett
1. Introduction ................................................................................... 61
2. Some Historical Observations ......................................................... 62
3. How Many Electrical Synapses Are There? ...................................... 66
4. Flexibility in Electrotonically Coupled Systems ............................... 67
5. Ca2+, H+ and Other Extrinsic Modulators
of Junctional Conductance ............................................................. 69
6. Voltage Dependence of Junctional Conductance ............................ 70
7. Summary ........................................................................................ 74
5. Cell Coupling in the Retina ...................................................... 79
David l Vaney
1. Introduction: A Model System for Studying Cell Coupling
in the Central Nervous System ........................................................ 79
2. Horizontal Cells Prove the Rules ofNeuronal Coupling ................. 81
3. Promises and Pitfalls of the Tracer-Coupling Technique ................. 85
4. Occurrence and Function of Heterologous Coupling in the Retina. 89
5. Patterns and Development of Coupling in Territorial Networks ..... 91
6. The Modulation of Gap Junction Permeability
in the Retina ........................................................................... 103
Reto Weiler
1. Introduction ................................................................................. 103
2. Horizontal Cell Coupling ............................................................. 104
3. Modulation of Rod-Cone Coupling by Light ................................ 115
4. Modulation of Coupling Between Amacrine Cells ........................ 116
7. Modulation of Connexon Density in Gap Junctions
of Fish Horizontal Cells .................................................•........ 123
Hartwig Walburg and Gertrud Kurz-Isler
1. Introduction ................................................................................. 123
2. Gap Junctions in the Vertebrate Retina ......................................... 124
3. Gap Junctions in Horizontal Cells ................................................ 124
4. Gap Junctions Respond on Different Illumination Conditions ..... 124
5. Gap Junctions Respond to Optic Nerve Crush and/or
Dopamine Treatment ................................................................... 127
6. Gap Junctions Respond to Variations of pH ................................. 129
8. Characterization and Regulation of Gap Junction Channels
in Cultured Astrocytes ............................................................ 135
Christian Giaume and Laurent Venance
1. Introduction ................................................................................. 136
2. Coupled Astrocytes Could Participate in Information Processing
in the Brain ................................................................................... 136
3. Connexin43 is the Major Junctional Protein in Astrocytes ............ 138
4. Short-Term Regulation of Gap Junction Permeability
in Astrocytes ................................................................................. 140
5. Putative Roles for Gap Junction Regulation in Astrocytes ............. 147
6. Conclusions and Perspectives ........................................................ 148
9. Do Glial Gap Junctions Play a Role in Extracellular Ion
Homeostasis? .......................................................................... 159
Bruce R. Ransom
1. Introduction ................................................................................. 159
2. [K•]o Would Accumulate to Disruptive Levels if Special Control
Mechanisms Did Not Operate ...................................................... 159
3. Are Gap Junctions Necessary for K• Spatial Buffering? .................. 163
4. Are Glial Gap Junctions Necessary for Direct K• Sequestration? ... 166
5. Is the Participation of Gap Junctions in [K+]o Homeostasis Under
Dynamic Control? ........................................................................ 166
6. Conclusions .................................................................................. 169
10. Subcellular Topography and Plasticity of Gap Junction
Distribution on Astrocytes .....................•.•••••.••....................... 175
Astrid Rohlmann and f. R. Wolff
1. Introduction ................................................................................. 175
2. Characterization of Astrocytic Morphology: Determinants
of Their Cell Biological Function .................................................. 176
3. Topography of Gap Junctions in Cortical Tissue on Identified
Astrocytes . . . . .. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. . . . . . . . 179
4. Plasticity of the Astrocytic Coupling ............................................. 186
5. A New Model of Gap Junction Coupling in the Astrocytic
Network ....................................................................................... 188
6. Conclusions and Outlook ............................................................. 190
11. Effect of Gap Junctional Communication on Glioma Cell
Function ................................................................................. 193
Christian C. G. Naus, john F. Becherger and Shari L. Bond
1. Introduction ................................................................................. 193
2. Gap Junctions in Astrocytes and Glioma Cells .............................. 193
3. Transfection of Glioma Cells ........................................................ 196
4. Summary ...................................................................................... 199
12. Gap-Junctional Communication in Mammalian Cortical
Astrocytes: Development, Modifiability and Possible
Functions ................................................................................ 203
Christian M Muller
1. Introduction ................................................................................. 203
2. Dye Coupling Among Astrocytes .................................................. 204
3. Topography of Dye Coupling ....................................................... 206
4. Development of Dye Coupling ..................................................... 207
5. Modification of Dye Coupling by Protein Kinase C and upon
Central Nervous System Damage .................................................. 208
6. Possible Function(s) of Gap Junctional Communication
Among Astrocytes ......................................................................... 209
13. Connexin32 and X-Linked-Charcot-Marie-Tooth Disease ..... 213
Suzanne M Deschenes, Linda ]o Bone, Kenneth H Fischbeck
and Steven S. Scherer
1. Summary ...................................................................................... 213
2. Historical Background .................................................................. 213
3. Connexin32 Mutations and CMTX ............................................. 216
4. Functional Analysis ofCx32 Mutations In Vitro ........................... 216
5. Cx32 Expression in Myelinating Cells ........................................... 219
6. Why Do Cx32 Mutations Primarily Affect the PNS? .................... 222
7. Animal Models and CMTX .......................................................... 223
14. Regulation of Connexin Expression in Schwann Cells .•.••....... 229
Karen J Chandross, David C. Spray and john A. Kessler
1. Summary ...................................................................................... 229
2. Introduction ................................................................................. 229
3. Connexins and Gap Junction Channels in Peripheral Nerve ......... 232
4. In Vitro Analysis ofSchwann Cell Gap Junctions ......................... 233
5. Cytokines and Schwann Cell Gap Junctions ................................. 234
6. Conclusions .................................................................................. 236
15. Gap Junction Expression in the Olfactory System .......••••....... 243
Fernando Miragall Otto Traub and RolfD ermietzel
1. Introduction ................................................................................. 243
2. Expression of Gap Junctions and Connexins
in the Olfactory Epithelium .......................................................... 244
3. Expression of Gap Junctions and Connexins
in the Olfactory Nerves ................................................................. 250
4. Expression of Gap Junctions and Connexins
in the Olfactory Bulb .................................................................... 252
5. Summary ...................................................................................... 258
16. Temporal Expression of Gap Junctions
During Neuronal Ontogeny ...•.•••••.••...•....................••..•.•••..... 261
Renata Rozental and David C. Spray
1. Introduction ................................................................................. 261
2. Gap Junctions in Development ..................................................... 263
3. Gap Junctions in Brain Development ........................................... 263
4. Temporal Expression of Gap Junctions and Development
ofVoltage- and Ligand-Gated Responses in Differentiating
Neuroblasts ................................................................................... 264
5. Conclusions and Prospects ............................................................ 273
17. Dendritic Gap Junctions in Developing Neocortex: A Possible
Route for Wave-Like Propagation of Neuronal Activity •••..•..• 279
Alejandro Peinado
1. Introduction ................................................................................. 279
2. Gap Junctions in Developing Neocortex ....................................... 281
3. Waves in Developing Neocortex ................................................... 282
4. Mechanisms Involved in Wave Propagation .................................. 283
5. Concluding Thoughts ................................................................... 287
18. Electric Coupling in Epileptogenesis ....................................... 289
Peter L. Carlen, jose L. Perez-Velazquez, Taufik A. Valiante,
Shokrollah S. Jahromi and Berj L. Bardakjian
1. Introduction ................................................................................. 289
2. Historical Development ................................................................ 290
3. Connexins ..................................................................................... 291
4. Gap Junctions and Epileptogenesis ............................................... 291
5. Electric Coupling During Seizures ................................................ 292
6. Intrinsic Properties and Entrainment ............................................ 292
7. Modulation of Gap Junctions and Seizures ................................... 293
8. Spikelets: Possible Capacitive Coupling ........................................ 294
9. Differentiation of a Prejunctional Action Potential ....................... 295
19. Spreading Depression-A Gap Junction Mediated Event? ...... 301
Maiken Nedergaard and Steven Goldman
1. Introduction ................................................................................. 301
2. Gap Junction Mediated Signaling in Cultured Brain Cells ............ 303
3. Is Spreading Depression an Example of Gap Junction-Mediated
Signaling Within the Brain? .......................................................... 303
4. Prospects for the Future ................................................................ 311
Index .............................................................................................. 313
rr=================== AB BR EVIAT I0 NS = =====================il
Cx32 connexin32
Cx46 connexin46
Cx43 connexin43
F-BPE forskolin combined with GGF from bovine pituitary
extract
G. . steady state junctional conductance
GFAP glial fibrillary acidic protein
GGF glial growth factor
L-NGFR low affinity nerve growth factor receptor
MAG myelin-associated glycoprotein
MBP myelin basic protein
N-CAM neural cell adhesion molecules
NDF~ neu differentiation factor beta
NGF nerve growth factor
PCR polymerase chain reaction
protein zero
PMP-22 peripheral myelin protein-22
TGF~ transforming growth factor beta
TNF a tumor necrosis factor alpha
transjunctional voltage
