Journal of Neuroscience, Vol 12, 2112-2119, Copyright © 1992 by Society for Neuroscience
Antibody neutralization of neurite growth inhibitors from oligodendrocytes results in expanded pattern of postnatally sprouting retinocollicular axons
JP Kapfhammer, ME Schwab and GE Schneider
Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge 02139.
After early postnatal ablation of one superior colliculus together with the
ipsilateral eye in Syrian hamsters, retinofugal fibers abnormally cross the
tectal midline and innervate the remaining superior colliculus. The fibers
of this aberrant decussation are confined mainly to the superficial gray
layer, with little ingrowth or termination in the deeper stratum opticum;
laterally, most termination is in the superficial part of the superficial
gray. Establishment of this abnormal pattern is temporally correlated with
the appearance of oligodendrocytes at progressively more superficial
locations in the colliculus. Oligodendrocytes express, on their surface,
molecules that are inhibitory to neurite growth. This raises the
possibility that their differential distribution in the superior colliculus
during growth of retinal fibers is causally involved in the generation of
the observed termination pattern. We tested this hypothesis by applying the
monoclonal antibody IN-1, which neutralizes this inhibitory activity,
during the time of postnatal fiber growth and terminal arbor formation. We
found that in the presence of IN-1, but not a control antibody, recrossing
retinofugal fibers, observed at postnatal day 12, traverse the stratum
opticum as well as the superficial gray, with greater depth of termination
in superficial gray and stratum opticum. This pattern resembles that of the
normal contralateral retinotectal projection. The results indicate that
neurite growth inhibitors expressed by oligodendrocytes are responsible for
restricting the innervation of a target area in postnatal plasticity.
.gif?ad=17923&adview=true)
Previous Article | Next Article
