Loss of auditory activity modifies the location of potassium channel KCNQ5 in auditory brainstem neurons.
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.
Affiliation: Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain.Show MeSH
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Mentions: Regulation of KCNQ5 levels 40 days after cochlear removal was also analyzed by Western blotting (Fig. 3A). The densitometry analysis revealed that the overall KCNQ5 protein density in the CN 40 days after cochlear removal was statistically similar to that of the controls (86.695% ± 25.15% compared with the control group; P = 0.5839, unpaired t-test with Welch's correction). Samples included tissue trace amounts from the dorsal cochlear nucleus (DCN). These results support the conclusion that de novo KCNQ5 immunolabeling in neuronal cell bodies of the AVCN 40 days after cochlear removal reflects protein accumulation at levels comparable to those found in normal animals in endbulbs of Held, which degenerated as a result of cochlear removal. As an internal positive control for Western blotting, we also tested the calretinin levels, which had dropped dramatically (about 60% compared with the control group; P < 0.001, unpaired t-test with Welch's correction) 40 days after bilateral cochlear ablation (Fig. 3A). This corroborated, at the same time, loss of the nerve fibers seen with immunocytochemistry and Fluoro-Jade labeling.
Affiliation: Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain.