Effects of cochlear ablation on amino acid concentrations in the chinchilla posteroventral cochlear nucleus, as compared to rat

Godfrey, Donald A.; Chen, K.; Godfrey, Matthew A.; Jin, Yongming; Robinson, K.T.; Hair, Caitlin E.

doi:10.1016/j.neuroscience.2007.12.031

Cited by 10 publications

(12 citation statements)

References 48 publications

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“…All of the procedures used in this study have been described previously (Lowry and Passonneau, 1972; Godfrey and Matschinsky, 1976; Godfrey et al, 1988, 2000, 2004b, 2008a,b; Ross et al, 1995; Li et al, 1996; Jin et al, 2005). …”

Section: Methodsmentioning

confidence: 99%

“…The eluate was passed through a Spectrovision fluorescence detector, and the peaks of fluorescence were quantitated via a computer using Millennium software (from Waters). Amino acids were identified by their retention times, and their levels were calculated by comparison to calibrated amino acid standard solutions included in the same assays (Hill et al, 1979; Ross et al, 1995; Godfrey et al, 2000, 2004b, 2008a). Standards were prepared from Standard H (from Pierce) supplemented with calibrated amounts of asparagine, glutamine, taurine, and GABA (from Sigma).…”

Section: Methodsmentioning

confidence: 99%

“…In the auditory system, damage to the cochlea part of the inner ear can result in hearing loss and distorted hearing, such as tinnitus ( Eggermont, 2012). Chemical changes associated with these deficits have been studied at many levels of the rodent auditory system (Fisher and Davies, 1976; Wenthold and Gulley, 1977; Wenthold, 1978, 1979; Ryan et al, 1992; Hackney et al, 1996; Abbott et al, 1999; Milbrandt et al, 2000; Potashner et al, 1985, 1997, 2000; Suneja et al, 1998a,b, 2000; Michler and Illing, 2003; Zhang et al, 2003a,b; Jin et al, 2005, 2006; Jin and Godfrey, 2006; Godfrey et al, 2008a,b, 2012, 2013; Wang et al, 2009, 2011; Dong et al, 2010; Hildebrandt et al, 2011; Kraus et al, 2011; Fredrich et al, 2013), but the most immediate effects occur at its earliest levels, where the auditory nerve carries information about sounds from the cochlea to the cochlear nucleus (Harrison and Warr, 1962; Harrison and Irving, 1965, 1966; Merchán et al, 1985). The superior olivary complex, which receives extensive input from the cochlear nucleus, is also connected to the cochlea via a centrifugal pathway, the olivocochlear bundle (Warr, 1992).…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies in rodents have indicated important functions for the amino acids glutamate, glycine, and γ-aminobutyrate (GABA) as major neurotransmitters in the cochlear nucleus (Fisher and Davies, 1976; Wenthold and Gulley, 1977; Wenthold, 1978, 1979; Hackney et al, 1996; Potashner et al, 1985, 1997, 2000; Suneja et al, 1998a,b, 2000; Godfrey et al, 2008a,b, 2012; Wang et al, 2009; Dong et al, 2010). Glutamate is strongly supported as a neurotransmitter of auditory nerve fibers, whereas glycine and GABA, as well as glutamate, are associated with cochlear nucleus interneurons and non-auditory nerve innervations (Godfrey et al, 2000, 2008b).…”

Section: Introductionmentioning

confidence: 99%

“…Some of the results for the PVCN were included in a previous publication (Godfrey et al, 2008a), but they are also included here for completeness.…”

Section: Introductionmentioning

confidence: 99%

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Effects of cochlear ablation on amino acid levels in the rat cochlear nucleus and superior olive

Godfrey¹,

Jin²,

Liu³

et al. 2014

Hearing Research

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Amino acids have important roles in the chemistry of the auditory system, including communication among neurons. There is much evidence for glutamate as a neurotransmitter from auditory nerve fibers to cochlear nucleus neurons. Previous studies in rodents have examined effects of removal of auditory nerve input by cochlear ablation on levels, uptake and release of glutamate in cochlear nucleus subdivisions, as well as on glutamate receptors. Effects have also been reported on uptake and release of γ-aminobutyrate (GABA) and glycine, two other amino acids strongly implicated in cochlear nucleus synaptic transmission. We mapped the effects of cochlear ablation on the levels of amino acids, including glutamate, GABA, glycine, aspartate, glutamine, taurine, serine, threonine, and arginine, in microscopic subregions of the rat cochlear nucleus. Submicrogram-size samples microdissected from freeze-dried brainstem sections were assayed for amino acid levels by high performance liquid chromatography. After cochlear ablation, glutamate and aspartate levels decreased by 2 days in regions receiving relatively dense innervation from the auditory nerve, whereas the levels of most other amino acids increased. The results are consistent with a close association of glutamate and aspartate with auditory nerve fibers and of other amino acids with other neurons and glia in the cochlear nucleus. A consistent decrease of GABA level in the lateral superior olive could be consistent with a role in some lateral olivocochlear neurons. The results are compared with those obtained with the same methods for the rat vestibular nerve root and nuclei after vestibular ganglionectomy.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Some of the results for the PVCN were included in a previous publication (Godfrey et al, 2008a), but they are also included here for completeness.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effects of cochlear ablation on amino acid levels in the rat cochlear nucleus and superior olive

Godfrey¹,

Jin²,

Liu³

et al. 2014

Hearing Research

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Volumes of cochlear nucleus regions in rodents

et al. 2016

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The cochlear nucleus receives all the coded information about sound from the cochlea and is the source of auditory information for the rest of the central auditory system. As such, it is a critical auditory nucleus. The sizes of the cochlear nucleus as a whole and its three major subdivisions – anteroventral cochlear nucleus (AVCN), posteroventral cochlear nucleus (PVCN), and dorsal cochlear nucleus (DCN) - have been measured in a large number of mammals, but measurements of its subregions at a more detailed level for a variety of species have not previously been made. Size measurements are reported here for the summed granular regions, DCN layers, AVCN, PVCN, and interstitial nucleus in 15 different rodent species, as well as a lagomorph, carnivore, and small primate. This further refinement of measurements is important because the granular regions and superficial layers of the DCN appear to have some different functions than the other cochlear nucleus regions. Except for DCN layers in the mountain beaver, all regions were clearly identifiable in all the animals studied. Relative regional size differences among most of the rodents, and even the 3 non-rodents, were not large and did not show a consistent relation to their wide range of lifestyles and hearing parameters. However, the mountain beaver, and to a lesser extent the pocket gopher, two rodents that live in tunnel systems, had relative sizes of summed granular regions and DCN molecular layer distinctly larger than those of the other mammals. Among all the mammals studied, there was a high correlation between the size per body weight of summed granular regions and that of the DCN molecular layer, consistent with other evidence for a close relationship between granule cells and superficial DCN neurons.

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Amino acid and acetylcholine chemistry in the central auditory system of young, middle-aged and old rats

et al. 2017

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Effects of cochlear ablation on amino acid concentrations in the chinchilla posteroventral cochlear nucleus, as compared to rat

Cited by 10 publications

References 48 publications

Effects of cochlear ablation on amino acid levels in the rat cochlear nucleus and superior olive

Effects of cochlear ablation on amino acid levels in the rat cochlear nucleus and superior olive

Volumes of cochlear nucleus regions in rodents

Amino acid and acetylcholine chemistry in the central auditory system of young, middle-aged and old rats

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