Population and density of the bipolar ganglion cells in the cochlea of the harp seal (Pagophilus groenlandicus Erxleben, 1777)

1976 ◽  
Vol 54 (11) ◽  
pp. 1918-1926 ◽  
Author(s):  
F. Ramprashad
Keyword(s):  
Hair Cells ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Harp Seal ◽  
Nerve Cell Body ◽  
Continuous Ring ◽  
Average Value ◽  
Pagophilus Groenlandicus ◽  
Sensory Hair Cells ◽  
Two Peaks

The population and density of the bipolar ganglion cells were determined from serial horizontal sections and graphic reconstructions of the cochleas of five captive harp seals. The [Formula: see text]-turn spiral ganglion forms a continuous ring throughout its course except at the extreme basal end where it is narrowest. The nerve cell body is 25 μm long (16.1–38.8 μm) and 16 μm wide (10–24 μm). The average number of ganglion cells present was 57 185 (46 389 – 70 952), with a corrected total number of 52 000 ganglion cells. Two peaks are present in the density curve of the ganglion cells. The first was at 1–1.5 mm and the second at 20 mm, where 2620 cells/mm2 and 2250 cells/mm2 respectively are present.The ratio of total ganglion cells to total sensory hair cells was about 3:1. This ratio was not uniform throughout the length of the cochlea; it was 6:1 at 2–3 mm from the basal end and declined gradually to 3:1 at the apical end. The average total of ganglion cells in the harp seal exceeded the average value in humans, but did not exceed the values found in dolphins.

scholarly journals Neural stem cells injected into the sound-damaged cochlea migrate throughout the cochlea and express markers of hair cells, supporting cells, and spiral ganglion cells

2007 ◽  
Vol 232 (1-2) ◽  
pp. 29-43 ◽  
Author(s):  
Mark A. Parker ◽  
Deborah A. Corliss ◽  
Brianna Gray ◽  
Julia K. Anderson ◽  
Richard P. Bobbin ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Hair Cells ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Supporting Cells

scholarly journals PIN1 Protects Hair Cells and Auditory HEI-OC1 Cells against Senescence by Inhibiting the PI3K/Akt/mTOR Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yanzhuo Zhang ◽  
Zhe Lv ◽  
Yudong Liu ◽  
Huan Cao ◽  
Jianwang Yang ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Hair Cells ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Cell Senescence ◽  
Prolyl Isomerase ◽  
Age Related ◽  
Pin1 Protein

A growing amount of evidence has confirmed the crucial role of the prolyl isomerase PIN1 in aging and age-related diseases. However, the mechanism of PIN1 in age-related hearing loss (ARHL) remains unclear. Pathologically, ARHL is primarily due to the loss and dysfunction of hair cells (HCs) and spiral ganglion cells (SGCs) in the cochlea. Therefore, in this study, we aimed to investigate the role of PIN1 in protecting hair cells and auditory HEI-OC1 cells from senescence. Enzyme-linked immunosorbent assays, immunohistochemistry, and immunofluorescence were used to detect the PIN1 protein level in the serum of ARHL patients and C57BL/6 mice in different groups, and in the SGCs and HCs of young and aged C57BL/6 mice. In addition, a model of HEI-OC1 cell senescence induced by H2O2 was used. Adult C57BL/6 mice were treated with juglone, or juglone and NAC, for 4 weeks. Interestingly, we found that the PIN1 protein expression decreased in the serum of patients with ARHL, in senescent HEI-OC1 cells, and in the cochlea of aged mice. Moreover, under H2O2 and juglone treatment, a large amount of ROS was produced, and phosphorylation of p53 was induced. Importantly, PIN1 expression was significantly increased by treatment with the p53 inhibitor pifithrin-α. Overexpression of PIN1 reversed the increased level of p-p53 and rescued HEI-OC1 cells from senescence. Furthermore, PIN1 mediated cellular senescence by the PI3K/Akt/mTOR signaling pathway. In vivo data from C57BL/6 mice showed that treatment with juglone led to hearing loss. Taken together, these findings demonstrated that PIN1 may act as a vital modulator in hair cell and HEI-OC1 cell senescence.

Cochlear Changes in Patients with Type 1 Diabetes Mellitus

2005 ◽  
Vol 133 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Hisaki Fukushima ◽  
Sebahattin Cureoglu ◽  
Patricia A. Schachern ◽  
Takeshi Kusunoki ◽  
Mehmet F. Oktay ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Type 1 Diabetes ◽  
Type 1 Diabetes Mellitus ◽  
Hair Cells ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Temporal Bones ◽  
Lateral Walls

OBJECTIVE: To evaluate the effects of diabetes on cochlear elements in human beings. STUDY DESIGN AND SETTING: Twenty-six temporal bones (mean age, 37.5 years) with type 1 diabetes and 30 age-matched controls were examined by light microscopy. We compared the findings of cochlear vessels, hair cells, spiral ganglion cells, and cochlear lateral walls. RESULTS: In diabetics, the walls of vessels of the basilar membrane ( P < 0.001) and vessels of the stria vascularis were ( P < 0.01) significantly thicker in all turns and loss of outer hair cells (OHCs) was significantly greater in the lower basal turn ( P < 0.01). Atrophy of the stria vascularis in all turns ( P < 0.0001) and loss of spiral ligament cells in upper turns ( P < 0.01) were significantly higher than controls. No significant difference was obtained in the number of spiral ganglion cells between groups. CONCLUSION: This study suggests that type 1 diabetes mellitus can cause cochlear microangiopathy and subsequently degeneration of cochlear lateral walls and OHCs.

The harp seal, Pagophilus groenlandicus (Erxleben, 1777). VI. Structure of retina

1970 ◽  
Vol 48 (2) ◽  
pp. 367-370 ◽  
Author(s):  
A. R. Nagy ◽  
K. Ronald
Keyword(s):  
Ganglion Cells ◽  
Outer Nuclear Layer ◽  
Horizontal Cell ◽  
Single Layer ◽  
Amacrine Cells ◽  
Visual Sensitivity ◽  
Harp Seal ◽  
Pagophilus Groenlandicus ◽  
Area Centralis ◽  
Cell Processes

The retina of the harp seal (Pagophilus groenlandicus) was studied by means of the light microscope. Ganglion cells occupy a single layer. Thinly dispersed throughout this layer are giant ganglion cells. There is no area centralis. The inner nuclear layer consists of large horizontal cell processes with bipolar and amacrine cells between the horizontal cell processes. The outer nuclear layer is the thickest of all retinal layers. Its density is constant in the central and peripheral areas of the retina, similar to that found in the inner nuclear and ganglion layers. Only rod photoreceptors were found; therefore it is presumed that seals have no color vision. The tapetum covers an extensive area and is 32–34 cellular layers thick centrally, diminishing in thickness peripherally. The combination of tapetum and rod receptors makes possible excellent visual sensitivity to dim light.

Blebs in inner and outer hair cells: a pathophysiological hypothesis

2008 ◽  
Vol 122 (11) ◽  
pp. 1151-1155 ◽  
Author(s):  
R Ramírez-Camacho ◽  
J R García-Berrocal ◽  
A Trinidad ◽  
J M Verdaguer ◽  
J Nevado
Keyword(s):  
Hair Cells ◽  
Outer Hair Cell ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Organ Of Corti ◽  
Outer Hair Cells ◽  
Inner Hair Cells ◽  
Hearing Thresholds

AbstractIntroduction:The ototoxic effects of cisplatin include loss of outer hair cells, degeneration of the stria vascularis and a decrease in the number of spiral ganglion cells. Scanning microscopy has shown balloon-like protrusions (blebs) of the plasma membrane of inner hair cells following cisplatin administration. The present study was undertaken to identify the possible role of inner and outer hair cell blebs in the pathogenesis of cisplatin-induced ototoxicity.Materials and methods:Twenty-five guinea pigs were injected with cisplatin and their hearing tested at different time-points, before sacrifice and examination with scanning electron microscopy.Results and analysis:Seven animals showed blebs in the inner hair cells at different stages. Hearing thresholds were lower in animals showing blebs.Discussion:Cisplatin seems to be able to induce changes in inner hair cells as well as in other structures in the organ of Corti. Blebbing observed in animals following cisplatin administration could play a specific role in the regulation of intracellular pressure.

Auditory-Nerve Activity in Cats Exposed to Ototoxic Drugs and High-Intensity Sounds

1976 ◽  
Vol 85 (6) ◽  
pp. 752-768 ◽  
Author(s):  
Nelson Y. S. Kiang ◽  
M. Charles Liberman ◽  
Robert A. Levine
Keyword(s):  
Hair Cells ◽  
Auditory Nerve ◽  
High Intensity ◽  
Ganglion Cells ◽  
Tuning Curve ◽  
Spiral Ganglion ◽  
Normal Animal ◽  
Nerve Fibers ◽  
Significant Loss ◽  
Term Survival

The response characteristics of auditory-nerve fibers in normal cats are compared with those in cats exposed to kanamycin and high-intensity sounds. The pathophysiology is characterized by an elevation of the tuning-curve “tips,” which is sometimes associated with hypersensitivity of the “tails.” Plots of unit thresholds are correlated with patterns of sensory-cell losses in the cochlea. There can be significant shifts in unit threshold without significant loss of hair cells; however, significant hair cell loss is always accompanied by highly abnormal unit thresholds. The presence of inner hair cells seems to be essential for the long-term survival of spiral ganglion cells. An incidental observation is that in the “normal” animal there is almost always a prominent “notch” at 3–4 kHz in the plots of threshold at characteristic frequency, which may have been produced by environmental noise.

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