The role of PKCzeta in amikacin-induced apoptosis in the cochlea: prevention by aspirin.

Aminoglycoside antibiotics are ototoxic, inducing irreversible sensorineural hearing loss mediated by oxidative and excitotoxic stresses. The NF-kappaB pathway is involved in the response to aminoglycoside damage in the cochlea. However, the molecular mechanisms of this ototoxicity remain unclear.

Middle ear gas loss in inflammatory conditions: the role of mucosa thickness and blood flow.

Several middle ear (ME) pathologies are associated with ME gas deficit. These include in particular the chronic otitis media diseases that are associated with inflammation (hence, increased ME mucosal blood flow) and/or reduced Eustachian tube (ET) function. The present study models the trans-mucosal gas exchange in normal and inflamed middle ears of rats.

In vivo demonstration of the absorptive function of the middle ear epithelium.

The present study investigated in vivo fluid and ion transport across the middle ear epithelium. The tympanic membrane of rats was punctured under general anesthesia. A capillary tube was fitted to the external auditory canal and the bulla filled with various solutions.

Experimental model for investigating trans-mucosal gas exchanges in the middle ear of the rat.

Objective: The total pressure in the middle ear depends on the air composition of this gas pocket, i.e. on gas exchanges occurring through either the Eustachian tube (ET) or mucosa.

Influence of auditory deprivation upon the tonopic organization in the inferior colliculus: a Fos immunocytochemical study in the rat.

The frequency organization in the inferior colliculus of neonatally-deafened rats was investigated using electrical stimulation of the cochlea and immunoreactivity for Fos as a marker of neuronal activity. An electrode implanted either at the base or at the apex of the right cochlea delivered a unique 45-min stimulation at two different level intensities and at two time points, i.e.

Steroidogenic enzyme expression in the rat cochlea.

Objective: Steroid hormones, and particularly mineralocorticoids, are candidates for controlling the homeostasis of endolymph as steroid receptors are widely expressed in the cochlea. In contrast, experiments on adrenalectomized animals have shown that an absence of steroids had little effect on the ionic composition of endolymph and hearing ability. We thus hypothesized that local production of steroids in the inner ear may regulate cochlear fluid exchanges.

[Contribution to the study of endolymph homeostasis].

The secretory structures of the cochlea including stria vascularis and spiral ligament are responsible for the secretion of endolymph, a fluid characterized by a high potassium concentration [150-180 mM], a low sodium concentration [< 1 mM] and a positive potential [80-100 mV]. This intra-cellular-like fluid fills the endolymphatic compartment and is essential in the transduction process which takes place in the organ of Corti. Yet, the mechanisms which control the homeostasis of this fluid remain largely unknown.