Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9436666 | Hearing Research | 2005 | 15 Pages |
Abstract
When we disturbed the auditory input of the adult rat by cochleotomy or noise trauma on one side, several substantial anatomical, cellular, and molecular changes took place in the auditory brainstem. We found that: (1) cochleotomy or severe noise trauma both lead to a considerable increase of immunoreactivity of the growth-associated protein GAP-43 in the ventral cochlear nucleus (VCN) of the affected side; (2) the expression of GAP-43 in VCN is restricted to presynaptic endings and short fiber segments; (3) axon collaterals of the cholinergic medial olivocochlear (MOC) neurons are the path along which GAP-43 reaches VCN; (4) partial cochlear lesions induce the emergence of GAP-43 positive presynaptic endings only in regions tonotopically corresponding to the extent of the lesion; (5) judging from the presence of immature fibers and growth cones in VCN on the deafened side, at least part of the GAP-43 positive presynaptic endings appear to be newly formed neuronal contacts following axonal sprouting while others may be modified pre-existing contacts; and (6) GAP-43 positive synapses are formed only on specific postsynaptic profiles, i.e., glutamatergic, glycinergic and calretinin containing cell bodies, but not GABAergic cell bodies. We conclude that unilateral deafening, be it partial or total, induces complex patterns of reconnecting neurons in the adult auditory brainstem, and we evaluate the possibility that the deafness-induced chain of events is optimized to remedy the loss of a bilaterally balanced activity in the auditory brainstem.
Keywords
AVCNventral acoustic striaLateral Olivocochlear SystemVNTBCochlear lesionPVCNGAP-43ABCVCNLSOABRPBSVASDCNgamma-aminobutyric acidRegenerationSynaptic remodelingphosphate bufferdiamidino yellowgrowth associated protein-43lateral superior oliveFast BlueSOCMedial olivocochlear systemsuperior olivary complexPhosphate-buffered salineMitochondriaventral cochlear nucleusPosteroventral cochlear nucleusdorsal cochlear nucleusanteroventral cochlear nucleusauditory brainstem responsePlasticityavidin–biotin complexChATcholine acetyltransferaseSynaptic vesiclesGABA
Related Topics
Life Sciences
Neuroscience
Sensory Systems
Authors
Robert-Benjamin Illing, K. Suzanne Kraus, Markus A. Meidinger,