Repeated noise exposure induces inflammation and cellular adaptations in the peripheral central auditory system resulting pathophysiology of hearing loss. In this study, we analyzed mechanisms by which noise-induced inflammatory-related events cochlea activate glial-mediated responses cochlear nucleus (CN), first relay station pathway. The function, glial activation, modifications gene expression protein levels inflammatory mediators ultrastructural changes glial-neuronal interactions were...

Age-related hearing loss (ARHL) is one of the most frequent sensory impairments in senescence and a source important socio-economic consequences. Understanding pathological responses that occur central auditory pathway patients who suffer from this disability vital to improve its diagnosis treatment. Therefore, goal study was characterize age-related modifications brainstem (ABR) determine whether these functional might be accompanied by an imbalance between excitation inhibition cochlear...

Both age-related hearing loss (ARHL) and noise-induced (NIHL) may share pathophysiological mechanisms in that they are associated with excess free radical formation cochlear blood flow reduction, leading to damage. Therefore, it is possible short, but repeated exposures relatively loud noise during extended time periods, like leisure (i.e. musical devices concerts) or occupational exposures, add aging mechanisms, having an impact on the onset and/or progression of ARHL. Consequently, aim...

An appropriate conditioning noise exposure may reduce a subsequent noise-induced threshold shift. Although this “toughening” effect helps to protect the auditory system from traumatic exposure, mechanisms that regulate protective process are not fully understood yet. Accordingly, goal of present study was characterize physiological processes associated with ‘toughening’ and determine their relationship metabolic changes in cochlea cochlear nucleus (CN). Auditory brainstem responses (ABR)...

Abstract Neurons of the cochlear nuclei receive axosomatic endings from primary afferent fibers cochlea and have projections that diverge to form parallel ascending auditory pathways. These cells are characterized by neurochemical phenotypes such as levels calretinin. To test whether or not early deafferentation results in changes calretinin immunostaining nucleus, unilateral ablations were performed ferrets soon after hearing onset (postnatal day [P]30–P40). Two months later, well cell...

Abstract The removal of afferent activity has been reported to modify neuronal in the cochlear nucleus adult rats. After cell damage, microglial cells are rapidly activated, initiating a series cellular responses that influences function and survival. To investigate how this glial response occurs it might influence injured neurons, bilateral ablations were performed on rats examine short‐term (16 24 hours 4 7 days) long‐term (15, 30, 100 changes distribution morphology (immunostained with...

ABSTRACT One of the main mechanisms used by neurons and glial cells to promote repair following brain injury is upregulate activity‐dependent molecules such as insulin‐like growth factor 1 (IGF‐1) interleukin‐1β (IL‐1β). In auditory system, IGF‐1 crucial for restoring synaptic transmission hearing loss; however, whether IL‐1β also involved in this process unknown. study, we evaluated expression within ventral cochlear nucleus adult rats at 1, 7, 15, 30 days bilateral ablation. After lesion,...

The reverse transcriptase–quantitative polymerase chain reaction (RT–qPCR) requires adequate normalization in order to ensure accurate results. use of reference genes is the most common method normalize RT–qPCR assays; however, many studies have reported that expression frequently used more variable than expected, depending on experimental conditions. Consequently, proper validation stability an essential step when performing new gene studies. Despite fact has been widely elucidate molecular...

We live in a world continuously immersed noise, an environmental, recreational and occupational factor present almost every daily human activity. Exposure to high-level noise could affect the auditory function of individuals at any age, resulting condition called noise-induced hearing loss (NIHL). Given that by 2018, more than 400 million people worldwide were suffering from disabling about one-third involved over-exposure, which represents 100 people, this impairment serious health problem....

We have previously reported that young adult rats exposed to daily, short-duration noise for extended time periods, develop accelerated presbycusis starting at 6 months of age. Auditory aging is associated with progressive hearing loss, cell deterioration, dysregulation the antioxidant defense system, and chronic inflammation, among others. To further characterize cellular molecular mechanisms crossroads between age-related loss (ARHL), 3-month-old were a noise-accelerated (NAP) protocol...

The increasing rate of age-related hearing loss (ARHL), with its subsequent reduction in quality life and increase health care costs, requires new therapeutic strategies to reduce delay impact. goal this study was determine if ARHL could be reduced a rat model by administering combination antioxidant vitamins A, C, E acting as free radical scavengers along Mg++, known powerful cochlear vasodilator (ACEMg). Toward goal, young adult, 3 month-old Wistar rats were divided into two groups: one...

In this study, we used image analysis to assess changes in calretinin immunoreactivity the lateral (LSO) and medial (MSO) superior olivary nuclei ferrets 2 months after unilateral cochlear ablations at 30-40 days of age, soon hearing onset. These two are first significant sites binaural convergence ascending auditory system, both receive direct projections from deafferented nucleus. Cochlear ablation results a decrease overall level immunostaining within LSO ipsilaterally compared with...

The ability of cat superior colliculus (SC) neurons to integrate information from different senses is thought depend on direct projections regions along the anterior ectosylvian sulcus (AES). However, electrical stimulation AES also activates SC output polysynaptically. In present study, we found that nitric oxide (NO)-containing (nitrergic) interneurons are a target projections, forming component this cortico-SC circuitry. dendritic and axonal processes these corticorecipient nitrergic...

Corticofugal projections to the thalamus reveal 2 axonal morphologies, each associated with specific physiological attributes. These determine functional characteristics of thalamic neurons. It is not clear, however, whether such features characterize corticofugal that mediate multisensory integration in superior colliculus (SC) The cortico-collicular from cat anterior ectosylvian sulcus (AES) are derived its visual, auditory, and somatosensory representations critical for integration....

Summary: Purpose: This study was performed to evaluate whether audiogenic seizures, in a strain of genetically epilepsy‐prone hamsters (GPG/Vall), might be associated with morphologic alterations the cochlea and auditory brainstem. In addition, we used parvalbumin as marker neurons high levels activity examine changes within neurons. Methods : Cochlear histology well immunohistochemistry were assess possible abnormalities GPG/Vall hamster. Densitometry also quantify immunostaining fibers...

Abstract In many systems, including ascending auditory pathways, calcium‐binding proteins are markers of specific neuronal circuits. Previous studies suggest that calretinin immunostaining may be a marker for circuits in the inferior colliculus (IC) code timing information. We undertook experiments to determine changes IC take place response cochlear ablation. Cochlear ablation was performed unilaterally ferrets just after hearing onset. Animals survived 2–3 months and brains were then...

Insulin-like growth factor 1 (IGF-1) is a powerful regulator of synaptic activity and deficit in this protein has profound impact on neurotransmission, mostly excitatory synapses both the developing mature auditory system. Adult Igf1-/- mice are animal models for study human syndromic deafness; they show altered cochlear projection patterns into abnormally developed neurons along with impaired glutamate uptake nuclei, phenomena that probably reflect disruptions neuronal circuits. To...

Noise induces oxidative stress in the cochlea followed by sensory cell death and hearing loss. The proof of principle that injections antioxidant vitamins Mg2+ prevent noise-induced loss (NIHL) has been established. However, effectiveness oral administration remains controversial otoprotection mechanisms are unclear. Using auditory evoked potentials, quantitative PCR, immunocytochemistry, we explored effects A, C, E, (ACEMg) on function survival following NIHL rats. Oral ACEMg reduced...