Sound overstimulation and exposure to ototoxic drugs damage cochlear hair cells (HCs) and cause their death. The surrounding support cells maintain an epithelial barrier and the appropriate physiological environment for surviving HCs during pathological conditions. Coordination of this homeostatic process requires cellular signalling. However, the signalling events that are activated during dam...

Cochlear damage can change the spontaneous firing rates of neurons in the dorsal cochlear nucleus (DCN). Increased spontaneous firing rates (hyperactivity) after acoustic trauma have been observed in the DCN of rodents such as hamsters, chinchillas and rats. This hyperactivity has been interpreted as a neural correlate of tinnitus. In cats, however, the spontaneous firing rates of DCN neurons w...

The aim of the present study was to observe the histological changes in the peripheral auditory system in rats at different time-points after relocating from low altitude to high altitude (3,600 m). The general physical condition of the rats was observed and cochlear tissue samples were obtained every month. The morphology and survival of the cochlear hair cells (HCs) were observed using cochle...

Although protective effects of the cochlea's efferent feedback pathways have been well documented, prior work has focused on hair cell damage and cochlear threshold elevation and, correspondingly, on the high sound pressure levels (>100 dB SPL) necessary to produce them. Here we explore the noise-induced loss of cochlear neurons that occurs with lower-intensity exposures and in the absence of p...

background outer hair cells' (ohcs') dysfunctions as the extent of temporary and permanent threshold shifts (tts and pts) and cochlear damage were assessed in rabbits exposed to continuous noise methods twelve new zealand white rabbits were studied in noise (n) (n=6; exposed to continuous noise; 95 db spl, 500-8000 hz for 8 h per day during 5 consecutive days) and control (c) (n=6; no...

The mammalian cochlea is a highly complex structure which contains several cells, including sensory receptor or hair cells. The main function of the cochlear hair cells is to convert the mechanical vibrations of the sound into electrical signals, then these signals travel to the brain along the auditory nerve. Auditory hair cells in some amphibians, reptiles, fish, and birds can regenerate or r...

It is increasingly appreciated that cochlear pathology is accompanied by adaptive responses in the central auditory system. The cause of cochlear pathology varies widely, and it seems that few commonalities can be drawn. In fact, despite intricate internal neuroplasticity and diverse external symptoms, several classical injury models provide a feasible path to locate responses to different peri...

Overexposure to intense sound can cause temporary or permanent hearing loss. Postexposure recovery of threshold sensitivity has been assumed to indicate reversal of damage to delicate mechano-sensory and neural structures of the inner ear and no persistent or delayed consequences for auditory function. Here, we show, using cochlear functional assays and confocal imaging of the inner ear in mous...

Introduction The structural changes underlying permanent noise-induced hearing loss (NIHL) include loss of the sensory hair cells, damage to their stereocilia, and supporting tissues within the cochlear lateral wall. Objective The objective of this study is to demonstrate curcumin as a safe and effective therapeutic agent in the prevention and treatment for fibroblasts damage within the cochlea...

Growing evidence suggests that cochlear stressors as noise exposure and aging can induce homeostatic/maladaptive changes in the central auditory system from the brainstem to the cortex. Studies centered on such changes have revealed several mechanisms that operate in the context of sensory disruption after insult (noise trauma, drug-, or age-related injury). The oxidative stress is central to c...