REEMERGENCE OF GAP-43 IN COCHLEAR NUCLEUS AND SUPERIOR OLIVE FOLLOWING COCHLEAR ABLATION IN THE RAT

The effect of cochlear lesion on the expression of the growth associat ed protein GAP-43 in superior olive and cochlear nucleus was studied i n the rat. In normal development of these auditory brainstem nuclei, G AP-43 immunoreactivity is high perinatally but low 10 days postnatally or thereafter. Removal of one spiral ganglion in grown-up animals cau sed a substantial re-emergence of GAP-43 immunoreactivity in varicose fibers of the ipsilateral ventral cochlear nucleus and cell bodies of the lateral superior olive. These findings suggest that a reactive syn aptogenesis takes place in the cochlear nucleus as a consequence of de afening through spiral ganglion loss.