Changes in plasma membrane structure and electromotile properties in prestin deficient outer hair cells

Physiological evidence has shown that cochlear outer hair cells (OHC) possess L-type voltage-dependent Ca2+ channels through which Ca2+ enters the OHC during depolarization. Their subcellular distribution has, however, remained unclear. In this study, the distribution of L-type Ca2+ channels on the basolateral plasma membrane of OHC has been demonstrated by the use of a laser scanning confocal microscope (LSCM) and a fluorescent probe DMBODIPY-DHP. The fluorescent staining pattern on the basolateral wall is nonuniform, suggesting a heterogeneous distribution of the channels in the plasma membrane. Direct imaging of intracellular Ca2+ visualized in real time by means of the LSCM and the fluorescent Ca2+ probe fluo 3 revealed temporal and spatial integration of Ca2+ movements and Ca2+ channel distribution. Exposure to high-K+ solution induced heterogeneity in the subcellular increase in the intracellular Ca2+ concentration. These results suggest that the heterogeneous distribution of L-type Ca2+ channels on the basolateral membrane might induce heterogeneous intracellular Ca2+ distribution during electrical activity in the OHC.

Download Full-text

Microdomains Displace Laterally and Rotate in the Plasma Membrane of Cochlear Outer Hair Cells

Biophysical Journal ◽

10.1016/j.bpj.2011.11.1652 ◽

2012 ◽

Vol 102 (3) ◽

pp. 298a-299a

Author(s):

Rei Kitani ◽

Federico Kalinec

Keyword(s):

Plasma Membrane ◽

Hair Cells ◽

Outer Hair Cells

Download Full-text

Time evolution of noise induced oxidation in outer hair cells: Role of NAD(P)H and plasma membrane fluidity

Biochimica et Biophysica Acta (BBA) - General Subjects ◽

10.1016/j.bbagen.2014.04.005 ◽

2014 ◽

Vol 1840 (7) ◽

pp. 2192-2202 ◽

Cited By ~ 32

Author(s):

Giuseppe Maulucci ◽

Diana Troiani ◽

Sara Letizia Maria Eramo ◽

Fabiola Paciello ◽

Maria Vittoria Podda ◽

...

Keyword(s):

Plasma Membrane ◽

Membrane Fluidity ◽

Time Evolution ◽

Hair Cells ◽

Outer Hair Cells ◽

Plasma Membrane Fluidity

Download Full-text

Further studies on the ultrastructure of the cochlea

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159746 ◽

1990 ◽

Vol 48 (3) ◽

pp. 440-441

Author(s):

Zhixian Wang ◽

Pinjin Zhu ◽

Jianhe Sun ◽

Xuezheng Song

Keyword(s):

Hair Cells ◽

Military Medicine ◽

Outer Hair Cells ◽

Apical Surface ◽

Epithelial Surface ◽

Hearing Research ◽

New Findings ◽

Fine Structures ◽

Temporal Bones ◽

Accurate Observation

Hearing research is important not only for clinical, professional and military medicine, but also for toxicology, gerontology and genetics. Ultrastructure of the cochlea attracts much attention of electron microscopists, (1―3) but the research lags far behind that of the other parts of the organnism. On the basis of careful microdissection, technical improvment and accurate observation, we have got some new findings which have not been reported in the literature.We collected four cochleas from human corpses. Temporal bones dissected 1 h after death and cochleas perfused with fixatives 4 h after death were good enough in terms of preservation of fine structures. SEM:The apical surface of OHCs (Outer hair cells) and DTs (Deiters cells) is narrower than that of IPs (Inner pillar cells). The mosaic configuration of the reticular membrane is not typical. The stereocilia of IHCs (Inner hair cells) are not uniform and some kinocilia could be seen on the OHCs in adults. The epithelial surface of RM (Reissner’s membrane) is not smooth and no mesh could be seen on the mesothelial surface of RM. TEM.

Download Full-text

Pengaruh sisplatin dosis tinggi terhadap penurunan fungsi sel rambut luar koklea

Oto Rhino Laryngologica Indonesiana ◽

10.32637/orli.v40i2.1 ◽

2013 ◽

Vol 40 (2) ◽

Author(s):

Asti Kristianti ◽

Teti Madiadipoera ◽

Bogi Soeseno

Keyword(s):

Hair Cells ◽

Malignant Neoplasm ◽

Otoacoustic Emission ◽

Outer Hair Cells ◽

High Dose ◽

Distortion Product Otoacoustic Emission ◽

Inclusion Criteria ◽

Cochlear Hair Cells ◽

Distortion Product ◽

Bilateral Sensorineural Hearing Loss

Background: Chemotherapy is worldwide used nowadays, and its toxicity still remain a problemespecially toxicity to the ear (ototoxicity). Cisplatin (cis-diamminedichloroplatinum) is one of themost commonly used chemotherapy and highly potent in treating epithelial malignancies. Ototoxicitycaused by cisplatin is irreversible, progressive, bilateral, sensorineural hearing loss especially on highfrequency (4-8 KHz) accompanied by tinnitus. Purpose: To observe the cochlear outer hair cells damagein malignancies patients treated with cisplatin. Methods: This study is an observational analytic studywith prospective design to determine the influence of high dose cisplatin on cochlear outer hair cellsfunction. The research was carried out at the ENT-HNS Department, Hasan Sadikin General HospitalBandung, from November 2007 until June 2008. Audiometry, tympanometry, and distortion productotoacoustic emission (DPOAE) examinations were conducted before chemotherapy and DPOAE, andtimpanometry was again measured three days after first and second cycles of cisplatin administration. McNemar test was performed to calculate the effects of high-dose cisplatin to the cochlear outer haircells function. To compare pre and post-cisplatin on alteration of cochlear hair cells function, Wilcoxontest was used. Results: In this study 60 ears from 30 subjects that meet the inclusion criteria, consistedof 25 man (83.3%) and 5 women (16.7%). The prevalence of damaged cochlear outer hair cells were63% at first cycle and 70% at second cycle of cisplatin administration. The decline of cochlear outerhair cells function was significant (p<0.001). Conclusion: High-dose cisplatin decreases cochlear outerhair cells function in patients with malignant neoplasm. Abstrak : Latar belakang: Kemoterapi sekarang rutin digunakan secara klinis di seluruh dunia. Sejalan denganhal tersebut toksisitas kemoterapi, khususnya terhadap telinga saat ini menjadi perhatian. Sisplatin(cis-diamminedichloroplatinum) adalah salah satu obat kemoterapi yang paling banyak digunakandan paling manjur untuk terapi keganasan epitelial. Efek ototoksik sisplatin yaitu terjadi gangguandengar sensorineural yang irreversible, progresif, bilateral pada frekuensi tinggi (4-8 kHz), dan disertaidengan tinitus. Tujuan: Untuk menilai penurunan fungsi sel rambut luar koklea pada penderita tumorganas sesudah pemberian sisplatin dosis tinggi dengan menggunakan DPOAE. Metode: Studi analitikobservasional dengan rancangan prospektif di Bagian IK. THT-KL RS. Hasan Sadikin Bandung mulaibulan November 2007 sampai dengan Juni 2008. Pada penelitian ini dilakukan pemeriksaan audiometrinada murni, timpanometri, dan distortion product otoacoustic emission (DPOAE) prakemoterapi, kemudianDPOAE dan timpanometri diulang tiga hari sesudah siklus pertama dan kedua kemoterapi sisplatin. Datayang diperoleh diuji dengan uji McNemar dan uji Wilcoxon. Hasil: Dari penelitian didapat 60 telingadari 30 subjek penelitian yang memenuhi kriteria inklusi yang terdiri dari 25 laki-laki (83,3%) dan 5perempuan (16,7%). Insidens penurunan fungsi sel rambut luar koklea sebesar 63% (38 kasus) sesudahsiklus pertama dan 70% (42 kasus) sesudah siklus kedua. Hubungan penurunan fungsi sel rambut luarkoklea memberikan nilai yang sangat bermakna sejak pemberian siklus pertama (p<0,001). Kesimpulan:Pemberian sisplatin dosis tinggi pada penderita tumor ganas menyebabkan penurunan fungsi sel rambutluar koklea.Kata kunci: kemoterapi, sisplatin dosis tinggi, sel rambut luar koklea.

Download Full-text