IBCN   20355
INSTITUTO DE BIOLOGIA CELULAR Y NEUROCIENCIA "PROFESOR EDUARDO DE ROBERTIS"
Unidad Ejecutora - UE
artículos
Título:
Key roles of Ephs and ephrins in retinotectal topographic map formation.
Autor/es:
SCICOLONE G; ORTALLI AL; CARRI NG
Revista:
BRAIN RESEARCH BULLETIN
Referencias:
Año: 2009 vol. 79 p. 227 - 247
ISSN:
0361-9230
Resumen:
Brain Res Bull. 2009 Jun 30;79(5):227-47. Epub 2009 Apr 1.
Key roles of Ephs and ephrins in retinotectal topographic map formation.
Scicolone G, Ortalli AL, Carri NG.
Institute
of Cell Biology and Neuroscience "Prof. E. De Robertis", School of
Medicine, University of Buenos Aires, 1121 Buenos Aires, Argentina.
gscicolo@mail.retina.ar
Cellular and
molecular mechanisms involved in the development of topographic ordered
connections in the central nervous system (CNS) constitute a key issue
in neurobiology because neural connectivities are the base of the CNS
normal function. We discuss the roles of the Eph/ephrin system in the
establishment of retinotopic projections onto the tectum/colliculus,
the most detailed studied model of topographic mapping. The expression
patterns of Ephs and ephrins in opposing gradients both in the retina
and the tectum/colliculus, label the local addresses on the target and
give specific sensitivities to growth cones according to their
topographic origin in the retina. We postulate that the highest levels
of these gradients could signal both the entry as well as the limiting
boundaries of the target. Since Ephs and ephrins are membrane-bound
molecules, they may function as both receptors and ligands producing
repulsive or attractant responses according to their microenvironment
and play central roles in a variety of developmental events such as
axon guidance, synapse formation and remodeling. Due to different
experimental approaches and the inherent species-specific differences,
some results appear contradictory and should be reanalyzed.
Nevertheless, these studies about the roles of the Eph/ephrin system in
retinotectal/collicular mapping support general principles in order to
understand CNS development and could be useful to design regeneration
therapies.