Wr. Henry et Mj. Mulroy, AFFERENT SYNAPTIC CHANGES IN AUDITORY HAIR-CELLS DURING NOISE-INDUCEDTEMPORARY THRESHOLD SHIFT, Hearing research, 84(1-2), 1995, pp. 81-90
This study presents evidence in support of the hypothesis that one of
the sites of failure during noise-induced temporary threshold shift (T
TS) is the afferent synapse between auditory hair cells and auditory n
erve fibers. Our results show clear evidence indicating changes in the
quantity of afferent synapses and the morphology of presynaptic struc
tures in the alligator lizard auditory hair cells during TTS. In TTS h
air cells there are statistically significant decreases in: 1) the num
ber of afferent synapses, 2) the number of synaptic vesicles at the af
ferent synapses, 3) the size of synaptic bodies, and 4) the packing de
nsity of synaptic vesicles around the synaptic body. These results sug
gest that the presynaptic components of the afferent synapse reflect t
he functional state of the synapse, and that the reduction of these sy
napses, both in number and component size, contributes to TTS.