Degeneration of cochlear neurons is the most commonly observed cellular cha
nge in the aging human and gerbil cochlea. Although it is unclear what lead
s to this neuronal loss, changes in the production of target-derived trophi
c factors may be the ultimate cause of cochlear neuron degeneration. The pr
esent study used an enzyme-linked immunosorbent assay to investigate whethe
r BDNF is produced by the organ of Corti or cochlear ganglia of young, midd
le aged, or aged gerbils. The results revealed an age-related increase in B
DNF in the organ of Corti, but not in the cochlear ganglia. (C) 2000 Academ
ic Press.