Analysis Tools
hearing/vestibular/ear
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• at P8 or later, the tectorial membrane appears deformed with a reduced limbal attachment zone and large holes within its matrix
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• at P8 or later, the tectorial membrane has large holes within its matrix
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• at P8 or later, the cross-sectional area of the tectorial membrane and longest vertical distance measured between its dorsal and ventral surface are doubled
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• in adult homozygotes, expression of the Ca2+-activated large conductance K+ (BK) channel alpha-subunit is significantly reduced in IHCs, suggesting a functional deficit in potassium current within the organ of Corti, despite the absence of IHC loss
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• in adult homozygotes, expression of the Ca2+-activated large conductance K+ (BK) channel alpha-subunit is significantly reduced at the base of OHCs, despite the absence of OHC loss
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• at 7 to 8 weeks of age, homozygotes produce poorly defined click-evoked ABR waveforms when attenuation is set at 0 or 5 dBA
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• at 7 to 8 weeks of age, homozygotes display no ABR responses at 10, 15, and 20 dBA
• at 7 to 8 weeks of age, homozygotes display a 42 dB sound pressure level threshold increase relative to wild-type or heterozygous mice
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• at 7 to 8 weeks of age, homozygotes exhibit profound hearing loss
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homeostasis/metabolism
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• homozygotes of both sexes exhibit a ~2-fold increase in serum concentrations of bone-derived alkaline phosphatase relative to wild-type littermates
• however, homozygotes are viable and fertile, with no significant differences in major organ histology, skeletal morphology, blood coagulation, liver weight, serum concentration of liver-derived proteins or response to induced septic shock relative to wild type littermates
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• at 7 weeks of age, homozygotes show a 43% reduction in free thyroxine (T4) levels in serum relative to wild-type mice
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nervous system
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• in adult homozygotes, expression of the Ca2+-activated large conductance K+ (BK) channel alpha-subunit is significantly reduced in IHCs, suggesting a functional deficit in potassium current within the organ of Corti, despite the absence of IHC loss
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• in adult homozygotes, expression of the Ca2+-activated large conductance K+ (BK) channel alpha-subunit is significantly reduced at the base of OHCs, despite the absence of OHC loss
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• homozygotes show abnormal compaction of the soma and fibers of spiral ganglion neurons, with empty spaces found between spiral ganglion
neurons and Schwann cells
• however, no cell loss occurs, as spiral ganglion neuron and Schwann cell densities remain normal
• this compaction defect appears to be associated with a specific down-regulation of expression of myelin basic protein (MBP) and myelin protein zero (P0) along the peripheral portion of the auditory nerve
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• adult homozygotes display defective myelination of the auditory nerve, resulting in abnormal compaction of spiral ganglion neurons
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endocrine/exocrine glands
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• adut homozygotes are hypothyroidic
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