Isoflurane anesthesia suppresses distortion product otoacoustic emissions in rats

Sheppard, Adam; Zhao, Dongyan; Salvi, Richard

doi:10.1016/j.joto.2018.03.002

Cited by 15 publications

(15 citation statements)

References 27 publications

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“…Nevertheless, it is puzzling to us that at P12 SLPs were observed without wave 1 responses, and that when present, wave 1 responses were observed without subsequent ABR waves. Although the functional changes observed in this study are consistent with an important contribution of conductive development to increased sensitivity (Figs 5 and 6 ) [ 43 , 44 ], the suppressive effects of isoflurane anesthesia on auditory responses should be considered as a potential confounding factor [ 45 – 47 ]. To address this issue, future studies are needed to define how functional parameters of early sensory responses are affected by the conscious state of the animal.…”

Section: Discussionsupporting

confidence: 61%

Defining the relationship between maternal care behavior and sensory development in Wistar rats: Auditory periphery development, eye opening and brain gene expression

et al. 2020

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Defining the relationship between maternal care, sensory development and brain gene expression in neonates is important to understand the impact of environmental challenges during sensitive periods in early life. In this study, we used a selection approach to test the hypothesis that variation in maternal licking and grooming (LG) during the first week of life influences sensory development in Wistar rat pups. We tracked the onset of the auditory brainstem response (ABR), the timing of eye opening (EO), middle ear development with micro-CT X-ray tomography, and used qRT-PCR to monitor changes in gene expression of the hypoxia-sensitive pathway and neurotrophin signaling in pups reared by low-LG or high-LG dams. The results show the first evidence that the transcription of genes involved in the hypoxia-sensitive pathway and neurotrophin signaling is regulated during separate sensitive periods that occur before and after hearing onset, respectively. Although the timing of ABR onset, EO, and the relative mRNA levels of genes involved in the hypoxia-sensitive pathway did not differ between pups from different LG groups, we found statistically significant increases in the relative mRNA levels of four genes involved in neurotrophin signaling in auditory brain regions from pups of different LG backgrounds. These results suggest that sensitivity to hypoxic challenge might be widespread in the auditory system of neonate rats before hearing onset, and that maternal LG may affect the transcription of genes involved in experience-dependent neuroplasticity.

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Section: Discussionsupporting

confidence: 61%

Defining the relationship between maternal care behavior and sensory development in Wistar rats: Auditory periphery development, eye opening and brain gene expression

et al. 2020

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“…Our methods for collecting and analyzing DPOAEs have been described in detail in previous publication [34, 35]. Briefly, DPOAEs were measured with the Smart Distortion Product Otoacoustic Emission System (version 4.53, Intelligent Hearing System, Miami, FL), using two primary tones (f1 and f2) with an f2/f1 ratio of 1.2.…”

Section: Methodsmentioning

confidence: 99%

Auditory central gain compensates for changes in cochlear output after prolonged low-level noise exposure

Sheppard

Liu

Ding

et al. 2018

Neuroscience Letters

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Remarkably, the central auditory system can modify the strength of its sound-evoked neural response based on prior acoustic experiences, a phenomenon referred to as central gain. Gain changes are well documented following traumatic noise exposure, but much less is known about central gain dynamics following prolonged exposure to low-level noise, a common acoustic experience in many urban and work environments. We recently reported that the neural output of the cochlea is reduced, while gain was enhanced in the inferior colliculus (IC) following a 5-week exposure to 75 dB noise. To determine if similar effects were present at even lower intensities, we exposed rats to a 65 dB noise expecting to see little to no change in the cochlea or IC. The exposure had little effect on distortion product otoacoustic emissions and did not cause any hair cell loss. However, the amplitude of the CAP, which reflects the neural output of cochlea, was depressed by 50–75%. Surprisingly, neural responses from the IC were enhanced up to 70%, mainly at frequency within the noise exposure band. One-week post-exposure, CAP amplitudes returned to normal at frequencies within or above the exposure band, whereas responses evoked by frequencies below the exposure band were enhanced by more than 80%. In contrast, IC responses below the exposure frequency were depressed 10–20% whereas responses within the exposure frequency band were enhanced 10–20%. Thus, the central auditory system dynamically up- and down-regulates its gain to maintain supra-threshold neural responses within a narrow homeostatic range; a function that likely contributes to the prevention of sounds from being perceived as muffled or too loud.

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“…During the procedure, rats where anesthetized using isoflurane (for induction 3% of and for anesthesia maintenance 1,5% isoflurane was used, flow speed 2 l/min medical oxygen). To avoid anesthesia effects on cochlear outer hair cell and cochlear amplifier function, only the right ear was tested first and animals were woken up (Sheppard et al, 2018). After one hour wash out period, the procedure was repeated to measure the left ear.…”

Section: Hearing Evaluationmentioning

confidence: 99%

Early intervention and lifelong treatment with GLP1 receptor agonist liraglutide in a Wolfram Syndrome rat model with an emphasis on visual neurodegeneration, sensorineural hearing loss and diabetic phenotype

Jagomäe

Seppa

Reimets

et al. 2021

Preprint

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BackgroundWolfram syndrome (WS), also known as a DIDMOAD (Diabetes Insipidus, early-onset Diabetes Mellitus, Optic nerve Atrophy and Deafness) is a rare autosomal disorder caused by mutations in the Wolframin1 ( WFS1 ) gene. Previous studies revealed that glucagonlike peptide-1 receptor agonist (GLP1 RA) anti-diabetic drugs are effective in delaying and restoring glucose control in WS animal models and patients. The GLP1 RA liraglutide has also been shown to have neuroprotective properties in aged WS rats, reducing neuroinflammation, retinal ganglion cell death and optic nerve degeneration. WS is an early-onset, chronical condition and, therefore, early diagnosis and lifelong pharmacological treatment is the best solution to control disease progression in WS patients. Hence, the aim of this study was to evaluate the efficacy of the long-term liraglutide treatment on progression of WS symptoms. For this purpose, 2-month-old WS rats were treated with liraglutide (0.4mg/kg/day) up to the age of 18 months and changes in diabetes markers, visual acuity, hearing sensitivity were monitored in vivo over the course of the 16-month treatment period. ResultsEarly and chronic (16-month) intervention with the GLP-1 RA liraglutide delayed the development of glucose intolerance in WS rats. At the end of the experiment, 91% of saline- and 55% of liraglutide-treated WS rats needed daily insulin supplementation. Liraglutide administration was effective in maintaining visual acuity in WS rats by stalling the progression of cataract, degeneration of retinal ganglion cells and of optic nerve atrophy. Prolonged liraglutide therapy could not prevent sensorineural hearing loss at low frequencies. ConclusionThe rat model of WS used in this study is an excellent predictive model for preclinical trials as it closely recapitulates the relative onset and severity of the main symptoms of WS observed in human patients. We found that a 16-month treatment with GLP1 receptor agonist liraglutide delays or prevents the onset of diabetes and protects against vision loss in a rat model of Wolfram syndrome. Therefore, early diagnosis and prophylactic treatment with the GLP-1R agonist liraglutide may also prove to be a promising treatment option for Wolfram syndrome patients by increasing the quality of life of WS patients.

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Isoflurane anesthesia suppresses distortion product otoacoustic emissions in rats

Cited by 15 publications

References 27 publications

Defining the relationship between maternal care behavior and sensory development in Wistar rats: Auditory periphery development, eye opening and brain gene expression

Defining the relationship between maternal care behavior and sensory development in Wistar rats: Auditory periphery development, eye opening and brain gene expression

Auditory central gain compensates for changes in cochlear output after prolonged low-level noise exposure

Early intervention and lifelong treatment with GLP1 receptor agonist liraglutide in a Wolfram Syndrome rat model with an emphasis on visual neurodegeneration, sensorineural hearing loss and diabetic phenotype

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