NT-3 COMBINED WITH CNTF PROMOTES SURVIVAL OF NEURONS IN MODIOLUS-SPIRAL GANGLION EXPLANTS

AUDITORY neurons depend upon the integrity of both their peripheral (a uditory hair cells) and central (cochlear nucleus) targets for surviva l. One proposed trophic mechanism is the production of neurotrophin-3 (NT-3) by auditory hair cells. Modiolus-spiral ganglion explants from adult rats that closely mirror cell-cell interactions and in vivo tiss ue relationships within this ganglion provide a model for testing trop hic factors. Brain derived neurotrophic factor (BDNF), NT-3 and ciliar y neurotrophic factor (CNTF) were tested for their ability, both indiv idually and in combination, to support neuronal survival. NT-3 was the strongest individual promoter of survival, while CNTF (a cytokine) wi th NT-3 (a neurotrophin) was the most effective combination for promot ing the survival of auditory neurons.