Gravity Receptor Aging in the CBA/CaJ Strain: A Comparison to Auditory Aging

Abstract

The CBA/CaJ mouse strain is commonly used as a control as it has no known genetic mutations affecting the inner ear, maintains hearing sensitivity throughout life, and serves as a background for creating new genetic strains. The purpose of the present study was to characterize the effects of age and gender on gravity receptor function and compare functional changes between auditory and vestibular modalities. Vestibular-evoked potentials (VsEPs), auditory brainstem responses (ABRs), and distortion product otoacoustic emissions were measured in 131 mice. VsEP thresholds deteriorated an average of 0.39 dB re: 1.0 g/ms per month and at the oldest ages (18-23 months old) showed an average loss of 49% of VsEP dynamic range. No significant gender differences were found for VsEPs. ABR thresholds increased by an average of 1.35, 1.38, and 1.15 dB pe SPL per month for ABR stimulus frequencies of 8, 16, and 32 kHz, respectively, demonstrating an average decrease in auditory dynamic range of 25-35% at advanced ages. Both modalities declined with age. Age-related decreases in gravity receptor sensitivity should be considered when using the CBA/CaJ strain for vestibular studies.

Deletion of Shank1 has minimal effects on the molecular composition and function of glutamatergic afferent postsynapses in the mouse inner ear

“…These data suggest that the absence of Shank1 does not disrupt synapse further along the auditory pathway. Although there were no effects of genotype on ABR thresholds, thresholds were elevated in both genotypes compared to CBA mice (Mock et al, 2011), suggesting mild hearing loss in both genotypes. This observation is consistent with a mild early onset hearing loss reported for the 129 mouse strain (Zheng et al, 1999), the background strain of these mice.…”

“…Auditory brainstem responses (ABRs) and vestibular sensory evoked potentials (VsEPs) were measured for Shank1 −/− and Shank1 +/+ littermates using methods similar to those described previously (Jones et al, 1999; Jones et al, 2004; Mock et al, 2011). Mice were anaesthetized via a ketamine (18 mg/mL) and xylazine (2 mg/mL) solution (5 to 7 µL/g body weight) injected intraperitoneally.…”

Progressive hearing loss and gradual deterioration of sensory hair bundles in the ears of mice lacking the actin-binding protein Eps8L2

“…VsEP thresholds were similar between heterozygous control (−9.00 ± 2.77 dB) and KO mice (−9.10 ± 3. 39 dB) at levels aligned with normal mice (19), which suggests that the general sensitivity of the vestibular organs is not impacted by the absence of Eps8L2. P1 latencies (Fig.…”

Spiral Ganglion Degeneration and Hearing Loss as a Consequence of Satellite Cell Death in Saposin B-Deficient Mice

“…Vestibular evoked potential (VsEP) recordings were based on the methods published previously (Jones et al, 1999(Jones et al, , 2004Mock et al, 2011) and are briefly described here. Animals (P15mo; B Ϫ/Ϫ , n ϭ 3; WT, n ϭ 5) were anesthetized with a ketamine/xylazine (18:2 mg/ml) mixture, 7 l per gram body weight, injected intraperitoneally.…”