The effect of combined administration of cadmium and furosemide on auditory function in the rat

“…Neurotoxicity of organic (MeHg) or inorganic (Hg 2 + ) mercury has been well documented in both humans [8,13,14,19,29,32,33,35,48] and experimental animals [1,11,28,29,31,40,47]. The developing premature and immature CNS is more sensitive to damage from MeHg than the adult CNS [8,13].…”

Section: Introductionmentioning

confidence: 99%

“…The auditory deficit extends almost over the entire frequency range of hearing, and in the most severe instances, Hg 2 + can lead to clinically significant auditory deficits [4,19,35]. The sensory cochlea and vestibular apparatus of the inner ear containing the hair cells and central auditory structures have been a target of Hg 2 + ototoxicity [4,9,14,16,17,24,26,35,40,43,47].…”

Section: Introductionmentioning

confidence: 99%

Mercury (Hg2+) suppression of potassium currents of outer hair cells

Guihua

Järlebark

Ulfendahl

et al. 2003

Neurotoxicology and Teratology

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The heavy metal mercury (Hg 2 + ) is an insidious environmental pollutant that causes toxic effects on sensory systems. It is well known that the group IIB divalent cation Hg 2 + is an inhibitor of the group I monovalent potassium (K + ) cation pore-forming channel in several biological preparations. Here, we used the whole cell patch clamp technique on freshly isolated outer hair cells (OHCs) of the guinea pig cochlea to record outward K + currents and inward K + currents treated with mercuric chloride (HgCl 2 ). HgCl 2 affected K + currents in a voltage-and dose-dependent manner. The effects of HgCl 2 at 1.0 -100 mM are more pronounced on onset peak current than on steady-state end current. HgCl 2 depolarized also the resting membrane potential. Although the effect of HgCl 2 at 1.0 mM was partially washed out over several minutes, the effects at 10 and 100 mM were irreversible to washout. Since K + channels of OHCs are targets for HgCl 2 ototoxicity, this may lead to auditory transduction problems, including a loss in hearing sensitivity. A better understanding of fundamental mechanisms underlying K + channelopathies in OHCs due to HgCl 2 poisoning may lead to better preventive or therapeutic agents. D

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“…Studies are currently underway to determine the effect of age and the mechanism by which Mn induces cell death in cells within the inner ear. Thus, Mn may join a list of other heavy metals such as Pb, Cd and Hg which are linked to hearing loss or cochlear pathology (Lasky et al, 2001, Murata et al, 1993, Ozcaglar et al, 2001, Rice and Gilbert, 1992, Wassick and Yonovitz, 1985, Whitworth et al, 1999, Yamamura et al, 1989)…”

Section: 0 Discussionmentioning

confidence: 99%

Manganese is toxic to spiral ganglion neurons and hair cells in vitro

Ding¹,

Roth

Salvi³

2011

NeuroToxicology

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Occupational exposure to high atmospheric levels of Mn produces a severe and debilitating disorder known as manganism characterized by extrapyramidal disturbances similar to that seen in Parkinson's disease. Epidemiological and case studies suggest that persistent exposures to Mn may have deleterious effects on other organs including the auditory system and hearing. Mn accumulates in the inner ear following acute exposure raising the possibility that it can damage the sensory hair cells that convert sound into neural activity or spiral ganglion neurons (SGN) that transmit acoustic information from the hair cells to the brain via the auditory nerve. In this paper we demonstrate for first time that Mn causes significant damage to the sensory hair cells, peripheral auditory nerve fibers (ANF) and SGN in cochlear organotypic cultures isolated from postnatal day three rats. The peripheral ANF that make synaptic contact with the sensory hair cells were particularly vulnerable to Mn toxicity; damage occurred at concentrations as low 0.01 mM and increased with dose and duration of Mn exposure. Sensory hair cells, in contrast, were slightly more resistant to Mn toxicity than the ANF. Mn induced an atypical pattern of sensory cell damage; Mn was more toxic to inner hair cells (IHC) than outer hair cells (OHC) and in addition, IHC loss was relatively uniform along the length of the cochlea. Mn also caused significant loss and shrinkage of SGN soma. These findings are the first to demonstrate that Mn can produce severe lesions to both neurons and hair cells in the postnatal inner ear.

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The effect of combined administration of cadmium and furosemide on auditory function in the rat

Cited by 23 publications

References 44 publications

Chemical exposure and hearing loss

Chemical exposure and hearing loss

Mercury (Hg2+) suppression of potassium currents of outer hair cells

Manganese is toxic to spiral ganglion neurons and hair cells in vitro

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