Gap Junctions in the Nervous System

A Cytoplasm Connexon or Hemichannel Cytoplasm external loop I - P. M. N-Termlnus Fig. 1. 1. Topology of gap junction channels. (A) Cap junction channels, extending from the cytoplasm of one cell to the cytoplasm of another, are formed by two connexons or hemichannels connected across extracellular space. (B) Each connexon is formed from six connexin subunits, each having four membrane-spanning domains and both amino and carboxyl termini within the cytoplasm. External/oops (I and II} are believed to provide the high affinity interactions between the hemichannels. 4 Gap }unctions in the Nervous System P-region of voltage sensitive nonjunctional molecules; these contributed disulfide 9 channels. And Delmar's group has ob bridges are presumably involved in intra tained evidence that intracellular acidifi connexin and inter-EL loop tertiary struc cation may result in a conformational ture. An old observation that should be change analogous to the ball and chain repeated stoichiometrically with modern techniques is that gap junction channels model of inactivation of voltage gated ionic can be split into connexons or hemi channels, whereby the carboxyl terminal channels using hyperosmotic disaccharide portion of connexin43 binds to CL, closing 23 solutions again implying that linkage is the channel. Higher order structure of the channel not covalent. is believed to consist of six connexins form ing the hemichannel or connexon in a 3.

Auteur
Rolf Dermietzel is Professor and head of the Department of Neuroanatomy and Molecular Brain Research at the Ruhr University in Bochum, Germany. He gained his PhD from the University Hospital in Essen, Germany, in 1970, before training in cell biology at the California Institute of Technology and the Marine Biological Institute in Woods Hole, MA.

Texte du rabat

This book deals with the types of gap junction proteins (connexins) and their distribution within the nervous system, the physiological properties of channels formed of each connexin, and the role of gap junction channels in functions of normal and pathological brain and peripheral nerve. Although glial tissue is emphasized, additional groups of chapters deal with neurons in the central nervous system and with the retina.

Contenu

1. Gap Junctions in the Nervous System: An Introduction.- 2. Molecular Diversity and Plasticity of Gap Junctions in the Nervous System.- 3. Physiological Properties of Gap Junction Channels in the Nervous System.- 4. Gap Junctions as Electrical Synapses.- 5. Cell Coupling in the Retina.- 6. The Modulation of Gap Junction Permeability in the Retina.- 7. Modulation of Connexon Density in Gap Junctions of Fish Horizontal Cells.- 8. Characterization and Regulation of Gap Junction Channels in Cultured Astrocytes.- 9. Do Glial Gap Junctions Play a Role in Extracellular Ion Homeostasis?.- 10. Subcellular Topography and Plasticity of Gap Junction Distribution on Astrocytes.- 11. Effect of Gap Junctional Communication on Glioma Cell Function.- 12. Gap Junctional Communication in Mammalian Cortical Astrocytes: Development, Modifiability and Possible Functions.- 13. Connexin32 and X-Linked-Charcot-Marie-Tooth Disease.- 14. Regulation of Connexin Expression in Schwann Cells.- 15. Gap Junction Expression in the Olfactory System.- 16. Temporal Expression of Gap Junctions During Neuronal Ontogeny.- 17. Dendritic Gap Junctions in Developing Neocortex: A Possible Route for Wave-Like Propagation of Neuronal Activity.- 18. Electric Coupling in Epileptogenesis.- 19. Spreading DepressionA Gap Junction Mediated Event?.