[The cochlear implant. Molecular arguments favouring early implantation].
BACKGROUND
An important factor in the clinical outcome of cochlear implantation is the age of the patient. Compared to older patients, children with congenital deafness have a better outcome when the implantation is made before the age of 2 years. The cause may lie in the molecular biology of the brain, which changes during postnatal maturation.


METHODS
Protein probes were obtained from tissue of the rat inferior colliculus at different ages. The probes were analyzed using 2-dimensional SDS electrophoresis.


RESULTS
The expression of GAP-43, a protein expressed by neurons during axonal outgrowth and synaptogenesis, and the total number of the protein species showed a significant reduction during ontogenesis. This shows that while neurons gradually assume their specific function, they downregulate GAP-43 and the molecular complexity decreases.


CONCLUSIONS
Due to a lack of neuronal pluripotency at later developmental stages, the flexibility to adapt to the afferent activation provided by a cochlear implant is increasingly limited.
Jung
C
C
Neurobiologisches Forschungslabor der Universitäts-HNO-Klinik Freiburg.
Illing
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RB
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001306:Auditory Pathways / Q000378:metabolism; D019929:Cochlear Implantation / Q000379:methods; D003054:Cochlear Implants; D019922:GAP-43 Protein / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D034381:Hearing Loss / Q000378:metabolism* / Q000534:rehabilitation; D007245:Inferior Colliculi / Q000378:metabolism*; D008967:Molecular Biology / Q000379:methods; D009473:Neuronal Plasticity; D051381:Rats
D019922:GAP-43 Protein