NT-3 HAS A TROPIC EFFECT ON PROCESS OUTGROWTH BY POSTNATAL AUDITORY NEURONS IN-VITRO

CONFOCAL analysis of early postnatal auditory neurones in a bicompartm ental culture system was used to test for chemoattractant properties o f NGF, BDNF and NT-3 on neuronal process outgrowth. NT-3 exerted a str ong tropic effect on neuritic outgrowth from auditory neurones in this system. BDNF and NGF did not have any tropic activity that directed p rocesses outgrowth from auditory neurones. However, BDNF was important for the support of neuronal survival in NGF-treated cultures and for neuritogenesis in NT-3-treated cultures. Since NT-3 has been identifie d as both a survival factor and a chemotropic agent for auditory neuro nes, it is likely that this neurotrophin will be a useful therapeutic agent in the treatment of damaged cochleae for the recovery of hearing .