Neurochemistry of Olivocochlear Neurons in the Hamster

Reuss, Stefan; Disque-Kaiser, Ursula; Antoniou-Lipfert, Patricia; Gholi, Maryam Najaf; Riemann, Elke; Riemann, Randolf

doi:10.1002/ar.20881

Cited by 18 publications

(10 citation statements)

References 70 publications

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“…Gel foam pellets (Gelita Tampon, Braun, Melsungen, Germany) were placed in the round window niche and moistened with 10 µL artificial perilymph. This method to localize OCN in the brainstem was used in a number of our previous studies (Reuss et al, , in press; Riemann and Reuss, ).…”

Section: Methodsmentioning

confidence: 99%

Absence of Early Neuronal Death in the Olivocochlear System Following Acoustic Overstimulation

Reuss

Closhen

Riemann

et al. 2015

The Anatomical Record

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This study was conducted to examine possible effects of noise trauma on olivocochlear (OC) neurons. Anesthetized rats were exposed to a continuous 10 kHz pure tone at 120 dB sound pressure level for 2 hrs. The effects of treatment were verified by recordings of auditory brainstem response and distortion product otoacoustic emission. Three or 8 days after acoustic trauma, rats received unilateral injections of an aqueous solution of the retrograde neuronal tracer Fluorogold (FG) into the scala tympani to identify OC neurons (OCN). Five days after FG injection, brains were perfusion-fixed, and brainstem sections were cut and analyzed with respect to FG-labeled neurons. We found that, in both groups, numbers of OCN were similar to that of controls. The incubation of a second set of sections with antibodies against choline-acetyltransferase (the enzyme responsible for acetylcholine synthesis) showed the cholinergic neurons of the brainstem, however, without suggesting differences between groups. Our study, the first to investigate noise trauma effects on identified OCN, revealed that no visible alterations occurred in 2 weeks following trauma, neither in identified OCN nor in cholineacetyltransferase-immunofluorescence. At this time, auditory brainstem response and distortion product otoacoustic emission measurements showed severe signs of hearing loss. The mechanisms leading to hearing loss upon noise trauma apparently do not involve degeneration of OCN. Anat Rec, 299:103-110, 2016. V C 2015 Wiley Periodicals, Inc.Abbreviations used: ABR 5 auditory brainstem response; ChAT 5 choline-acetyltransferase; DPOAE 5 distortion product otoacoustic emission; FG 5 Fluorogold; IHC 5 inner hair cells; LOC/MOC 5 lateral/medial olivocochlear neurons; LSO 5 lateral superior olive; OC 5 olivocochlear; OCN 5 olivocochlear neurons; OHC 5 outer hair cells; PBS 5 phosphate-buffered 0.9% saline; RPO 5 rostral paraolivary region; RT 5 room temperature; SOC 5 superior olivary complex; SPL 5 sound pressure level; VNTB 5 ventral nucleus of the trapezoid body Grant sponsor: R€ ottger-Stiftung; Grant sponsor: HoffmannKlose-Stiftung.

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Section: Methodsmentioning

confidence: 99%

Absence of Early Neuronal Death in the Olivocochlear System Following Acoustic Overstimulation

Reuss

Closhen

Riemann

et al. 2015

The Anatomical Record

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“…We described altered expression of PAC1-R in PACAP-deficient mice cochlea compared to wild-type mice (Tamas et al 2012 ). The modulatory character of PACAP has also been reported in the superior olive, which is considered to be a major complex involved in multiple aspects of hearing (Reuss et al 2009 ).…”

Section: Discussionmentioning

confidence: 97%

Protective Effects of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Against Oxidative Stress in Zebrafish Hair Cells

et al. 2016

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Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic neuropeptide, with known antiapoptotic functions. Our previous in vitro study has demonstrated the ameliorative role of PACAP-38 in chicken hair cells under oxidative stress conditions, but its effects on living hair cells is now yet known. Therefore, the aim of the present study was to investigate in vivo the protective role of PACAP-38 in hair cells found in zebrafish (Danio rerio) sense organs—neuromasts. To induce oxidative stress the 5-day postfertilization (dpf) zebrafish larvae were exposed to 1.5 mM H2O2 for 15 min or 1 h. This resulted in an increase in caspase-3 and p-38 MAPK level in the hair cells as well as in an impairment of the larvae basic behavior. To investigate the ameliorative role of PACAP-38, the larvae were incubated with a mixture of 1.5 mM H2O2 and 100 nM PACAP-38 following 1 h preincubation with 100 nM PACAP-38 only. PACAP-38 abilities to prevent hair cells from apoptosis were investigated. Whole-mount immunohistochemistry and confocal microscopy analyses revealed that PACAP-38 treatment decreased the cleaved caspase-3 level in the hair cells, but had no influence on p-38 MAPK. The analyses of basic locomotor activity supported the protective role of PACAP-38 by demonstrating the improvement of the fish behavior after PACAP-38 treatment. In summary, our in vivo findings demonstrate that PACAP-38 protects zebrafish hair cells from oxidative stress by attenuating oxidative stress-induced apoptosis.

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“…For double-immunostaining experiments, selected sections were incubated in primary Cygb-antibody as described above and simultaneously, in either a polyclonal sheep antibody raised against (nNOS, 1:50, Abcam, Cambridge, UK) or a mouse monoclonal antibody raised against tyrosine hydroxylase (TH, 1:200, Chemicon, Temecula, CA, USA). Both antibodies were used and characterized in our laboratory previously (Reuss et al, 2009a , b ). The additional primary antibodies were visualized using Cy2-conjugated F(ab′)2-fragments of anti-sheep or anti-mouse IgG (Dianova) at 1:300 dilution.…”

Section: Methodsmentioning

confidence: 99%

Distribution of Cytoglobin in the Mouse Brain

et al. 2016

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Cytoglobin (Cygb) is a vertebrate globin with so far poorly defined function. It is expressed in the fibroblast cell-lineage but has also been found in neurons. Here we provide, using immunohistochemistry, a detailed study on the distribution of Cygb in the mouse brain. While Cygb is a cytoplasmic protein in active cells of the supportive tissue, in neurons it is located in the cytoplasm and the nucleus. We found the expression of Cygb in all brain regions, although only a fraction of the neurons was Cygb-positive. Signals were of different intensity ranging from faint to very intense. Telencephalic neurons in all laminae of the cerebral cortex (CCo), in the olfactory bulb (in particular periglomerular cells), in the hippocampal formation (strongly stained pyramidal cells with long processes), basal ganglia (scattered multipolar neurons in the dorsal striatum, dorsal and ventral pallidum (VP)), and in the amygdala (neurons with unlabeled processes) were labeled by the antibody. In the diencephalon, we observed Cygb-positive neurons of moderate intensity in various nuclei of the dorsal thalamus, in the hypothalamus, metathalamus (geniculate nuclei), epithalamus with strong labeling of habenular nucleus neurons and no labeling of pineal cells, and in the ventral thalamus. Tegmental neurons stood out by strongly stained somata with long processes in, e.g., the laterodorsal nucleus. In the tectum, faintly labeled neurons and fibers were detected in the superior colliculus (SC). The cerebellum exhibited unlabeled Purkinje-neurons but signs of strong afferent cortical innervation. Neurons in the gray matter of the spinal cord showed moderate immunofluorescence. Peripheral ganglia were not labeled by the antibody. The Meynert-fascicle and the olfactory and optic nerves/tracts were the only Cygb-immunoreactive (Cygb-IR) fiber systems. Notably, we found a remarkable level of colocalization of Cygb and neuronal nitric oxide (NO)-synthase in neurons, which supports a functional association.

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Neurochemistry of Olivocochlear Neurons in the Hamster

Cited by 18 publications

References 70 publications

Absence of Early Neuronal Death in the Olivocochlear System Following Acoustic Overstimulation

Absence of Early Neuronal Death in the Olivocochlear System Following Acoustic Overstimulation

Protective Effects of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Against Oxidative Stress in Zebrafish Hair Cells

Distribution of Cytoglobin in the Mouse Brain

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