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Loss of auditory activity modifies the location of potassium channel KCNQ5 in auditory brainstem neurons.

Caminos E, Garcia-Pino E, Juiz JM - J. Neurosci. Res. (2014)

Bottom Line: The results were comparable after intracochlear TTX injection, which drastically reduced KCNQ5 immunostaining in MNTB calyces and increased immunolabeling in VCN cell bodies.Endbulbs of Held in the VCN also showed diminished KCNQ5 labeling after intracochlear TTX injection.These results show that peripheral activity from auditory nerve afferents is necessary to maintain the subcellular distribution of KCNQ5 in synaptic endings of the auditory brainstem.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain.

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Time course of degeneration in the AVCN after bilateral cochlear ablation. Representative micrographs from coronal sections of the AVCN (see inset) from an unmanipulated control rat, a rat surviving 3 days after bilateral cochlear ablation, and a rat surviving 40 days after bilateral cochlear ablation. A–C: Micrographs illustrate Fluoro-Jade staining. Compared with the control (A), intense Fluoro-Jade staining is observed in the fibers of the AVCN from rats 3 (B) and 40 (C) days after ablation. Note that all the staining is concentrated in the fibers scattered in the neuropil and that the somata are not stained (asterisks). D–F: High magnifications illustrate the calretinin immunoreactivity pattern in the AVCN. Strong immunoreactivity is distributed in the fiber bundles in the neuropil of the control sections (D). Calretinin immunoreactivity in fibers greatly diminished at 3 and 40 days after cochlear removal (E,F, respectively). Scale bars = 100 µm in the inset; 20 µm for A–C; 50 µm in F (applies to D–F). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]
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fig04: Time course of degeneration in the AVCN after bilateral cochlear ablation. Representative micrographs from coronal sections of the AVCN (see inset) from an unmanipulated control rat, a rat surviving 3 days after bilateral cochlear ablation, and a rat surviving 40 days after bilateral cochlear ablation. A–C: Micrographs illustrate Fluoro-Jade staining. Compared with the control (A), intense Fluoro-Jade staining is observed in the fibers of the AVCN from rats 3 (B) and 40 (C) days after ablation. Note that all the staining is concentrated in the fibers scattered in the neuropil and that the somata are not stained (asterisks). D–F: High magnifications illustrate the calretinin immunoreactivity pattern in the AVCN. Strong immunoreactivity is distributed in the fiber bundles in the neuropil of the control sections (D). Calretinin immunoreactivity in fibers greatly diminished at 3 and 40 days after cochlear removal (E,F, respectively). Scale bars = 100 µm in the inset; 20 µm for A–C; 50 µm in F (applies to D–F). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]

Mentions: Fluoro-Jade staining helped determine the time course of fiber degeneration in the CN after bilateral cochlear ablation (Fig. 4A–C). Control sections of the AVCN showed only background fluorescence (Fig. 4A). On days 3, 10, and 40 after cochlear removal, the coronal sections of the CN exhibited degenerated terminal and fiber fields labeled with Fluoro-Jade, which occupied the nerve root and a large area of the CN (Fig. 4B,C). In contrast, cell bodies of CN neurons were not labeled with Fluoro-Jade at either stage (Fig. 4B,C), suggesting that no transneuronal degeneration took place, at least in this experimental time window.


Loss of auditory activity modifies the location of potassium channel KCNQ5 in auditory brainstem neurons.

Caminos E, Garcia-Pino E, Juiz JM - J. Neurosci. Res. (2014)

Time course of degeneration in the AVCN after bilateral cochlear ablation. Representative micrographs from coronal sections of the AVCN (see inset) from an unmanipulated control rat, a rat surviving 3 days after bilateral cochlear ablation, and a rat surviving 40 days after bilateral cochlear ablation. A–C: Micrographs illustrate Fluoro-Jade staining. Compared with the control (A), intense Fluoro-Jade staining is observed in the fibers of the AVCN from rats 3 (B) and 40 (C) days after ablation. Note that all the staining is concentrated in the fibers scattered in the neuropil and that the somata are not stained (asterisks). D–F: High magnifications illustrate the calretinin immunoreactivity pattern in the AVCN. Strong immunoreactivity is distributed in the fiber bundles in the neuropil of the control sections (D). Calretinin immunoreactivity in fibers greatly diminished at 3 and 40 days after cochlear removal (E,F, respectively). Scale bars = 100 µm in the inset; 20 µm for A–C; 50 µm in F (applies to D–F). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig04: Time course of degeneration in the AVCN after bilateral cochlear ablation. Representative micrographs from coronal sections of the AVCN (see inset) from an unmanipulated control rat, a rat surviving 3 days after bilateral cochlear ablation, and a rat surviving 40 days after bilateral cochlear ablation. A–C: Micrographs illustrate Fluoro-Jade staining. Compared with the control (A), intense Fluoro-Jade staining is observed in the fibers of the AVCN from rats 3 (B) and 40 (C) days after ablation. Note that all the staining is concentrated in the fibers scattered in the neuropil and that the somata are not stained (asterisks). D–F: High magnifications illustrate the calretinin immunoreactivity pattern in the AVCN. Strong immunoreactivity is distributed in the fiber bundles in the neuropil of the control sections (D). Calretinin immunoreactivity in fibers greatly diminished at 3 and 40 days after cochlear removal (E,F, respectively). Scale bars = 100 µm in the inset; 20 µm for A–C; 50 µm in F (applies to D–F). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]
Mentions: Fluoro-Jade staining helped determine the time course of fiber degeneration in the CN after bilateral cochlear ablation (Fig. 4A–C). Control sections of the AVCN showed only background fluorescence (Fig. 4A). On days 3, 10, and 40 after cochlear removal, the coronal sections of the CN exhibited degenerated terminal and fiber fields labeled with Fluoro-Jade, which occupied the nerve root and a large area of the CN (Fig. 4B,C). In contrast, cell bodies of CN neurons were not labeled with Fluoro-Jade at either stage (Fig. 4B,C), suggesting that no transneuronal degeneration took place, at least in this experimental time window.

Bottom Line: The results were comparable after intracochlear TTX injection, which drastically reduced KCNQ5 immunostaining in MNTB calyces and increased immunolabeling in VCN cell bodies.Endbulbs of Held in the VCN also showed diminished KCNQ5 labeling after intracochlear TTX injection.These results show that peripheral activity from auditory nerve afferents is necessary to maintain the subcellular distribution of KCNQ5 in synaptic endings of the auditory brainstem.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain.

Show MeSH
Related in: MedlinePlus