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Comparative distribution of glutamate transporters and receptors in relation to afferent innervation density in the mammalian cochlea.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Furness, David N. Lawton, Deborah M. |
| Copyright Year | 2003 |
| Abstract | The local expression of proteins involved in handling glutamate may be regulated by the number and activity of synapses in regions of glutamatergic innervation. The systematically varying innervation of inner hair cells (IHCs) of the cochlea provides a model to test this suggestion. IHCs are glutamatergic and form a single row along the cochlear spiral. Along this row the number of afferent fibers terminating on IHCs increases toward the base, reaching a peak and thereafter declining. The afferents are segregated so that higher spontaneous rate fibers terminate on the pillar-cell side of the IHC and lower rate fibers terminate on the modiolar side. Using immunofluorescence and postembedding immunogold labeling, we investigated the distributions of the glutamate-aspartate transporter (GLAST or excitatory amino acid transporter 1), vesicular glutamate transporter (VGLUT1), and the AMPA receptor glutamate receptor 4 (GluR4) along the spiral. Immunofluorescent labeling for GLAST in IHC supporting cells increased in intensity to a peak in the region of 6-9 mm from the apex. Immunogold labeling for GLAST was greater overall in these cells in the 10 mm region than in the 1 mm region and also on the pillar-cell side of the IHC compared with the modiolar side. Immunogold labeling for GluR4 was confined to synaptic sites, represented by puncta in immunofluorescence. The relative numbers of puncta changed with a gradient similar to that of GLAST labeling. VGLUT1 labeling occurred in IHCs but showed no clear cochleotopic gradient. These data suggest that both the density of innervation and the activity levels of glutamatergic synapses may be involved in modulating regional expression of GLAST. |
| Starting Page | 2028 |
| Ending Page | 2032 |
| Page Count | 5 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.jneurosci.org/content/jneuro/23/36/11296.full.pdf |
| PubMed reference number | 14672993v1 |
| Volume Number | 23 |
| Issue Number | 36 |
| Journal | The Journal of neuroscience : the official journal of the Society for Neuroscience |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | AMPA Receptors APEX1 protein, human Amino Acids Aspartic Acid Cochlear structure Excitatory Amino Acid Transporter 1 GRIA4 gene Glutamate Receptor Glutamic Acid Handling (Psychology) Immunofluorescence assay Immunohistochemistry Mammals Membrane Transport Proteins SLC1A3 gene Synapses Tissue fiber Type 1 vestibular sensory cell nerve supply |
| Content Type | Text |
| Resource Type | Article |
