scholarly journals Electrical tuning and transduction in short hair cells of the chicken auditory papilla

2013 ◽  
Vol 109 (8) ◽  
pp. 2007-2020 ◽  
Author(s):  
Xiaodong Tan ◽  
Maryline Beurg ◽  
Carole Hackney ◽  
Shanthini Mahendrasingam ◽  
Robert Fettiplace
Keyword(s):  
Hair Cells ◽  
Calcium Binding ◽  
Outer Hair Cells ◽  
Basilar Papilla ◽  
Resting Potential ◽  
Auditory Nerve Fiber ◽  
Buffer Concentration ◽  
Short Hair ◽  
Open Probability ◽  
Calbindin D

The avian auditory papilla contains two classes of sensory receptor, tall hair cells (THCs) and short hair cells (SHCs), the latter analogous to mammalian outer hair cells with large efferent but sparse afferent innervation. Little is known about the tuning, transduction, or electrical properties of SHCs. To address this problem, we made patch-clamp recordings from hair cells in an isolated chicken basilar papilla preparation at 33°C. We found that SHCs are electrically tuned by a Ca2+-activated K+ current, their resonant frequency varying along the papilla in tandem with that of the THCs, which also exhibit electrical tuning. The tonotopic map for THCs was similar to maps previously described from auditory nerve fiber measurements. SHCs also possess an A-type K+ current, but electrical tuning was observed only at resting potentials positive to −45 mV, where the A current is inactivated. We predict that the resting potential in vivo is approximately −40 mV, depolarized by a standing inward current through mechanotransducer (MT) channels having a resting open probability of ∼0.26. The resting open probability stems from a low endolymphatic Ca2+ concentration (0.24 mM) and a high intracellular mobile Ca2+ buffer concentration, estimated from perforated-patch recordings as equivalent to 0.5 mM BAPTA. The high buffer concentration was confirmed by quantifying parvalbumin-3 and calbindin D-28K with calibrated postembedding immunogold labeling, demonstrating >1 mM calcium-binding sites. Both proteins displayed an apex-to-base gradient matching that in the MT current amplitude, which increased exponentially along the papilla. Stereociliary bundles also labeled heavily with antibodies against the Ca2+ pump isoform PMCA2a.

Two types of voltage-dependent potassium channels in outer hair cells from the guinea pig cochlea

1999 ◽  
Vol 277 (5) ◽  
pp. C913-C925 ◽  
Author(s):  
Thierry van den Abbeele ◽  
Jacques Teulon ◽  
Patrice Tran Ba Huy
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Basolateral Membrane ◽  
Outer Hair Cells ◽  
Catalytic Subunit ◽  
Patch Clamp Technique ◽  
Open Probability ◽  
Guinea Pig Cochlea ◽  
Voltage Dependent ◽  
Inside Out

Cell-attached and cell-free configurations of the patch-clamp technique were used to investigate the conductive properties and regulation of the major K+channels in the basolateral membrane of outer hair cells freshly isolated from the guinea pig cochlea. There were two major voltage-dependent K+ channels. A Ca2+-activated K+ channel with a high conductance (220 pS, P K/ P Na= 8) was found in almost 20% of the patches. The inside-out activity of the channel was increased by depolarizations above 0 mV and increasing the intracellular Ca2+concentration. External ATP or adenosine did not alter the cell-attached activity of the channel. The open probability of the excised channel remained stable for several minutes without rundown and was not altered by the catalytic subunit of protein kinase A (PKA) applied internally. The most frequent K+ channel had a low conductance and a small outward rectification in symmetrical K+ conditions (10 pS for inward currents and 20 pS for outward currents, P K/ P Na= 28). It was found significantly more frequently in cell-attached and inside-out patches when the pipette contained 100 μM acetylcholine. It was not sensitive to internal Ca2+, was inhibited by 4-aminopyridine, was activated by depolarization above −30 mV, and exhibited a rundown after excision. It also had a slow inactivation on ensemble-averaged sweeps in response to depolarizing pulses. The cell-attached activity of the channel was increased when adenosine was superfused outside the pipette. This effect also occurred with permeant analogs of cAMP and internally applied catalytic subunit of PKA. Both channels could control the cell membrane voltage of outer hair cells.

Morphological and functional aspects of two different types of hair cells in the goldfish sacculus

1989 ◽  
Vol 62 (6) ◽  
pp. 1330-1343 ◽  
Author(s):  
I. Sugihara ◽  
T. Furukawa
Keyword(s):  
Cell Body ◽  
Hair Cells ◽  
The Other ◽  
Resting Potential ◽  
K Channel ◽  
Short Hair ◽  
Current Clamp ◽  
Other Hand ◽  
Inwardly Rectifying ◽  
A Current

1. With the use of whole-cell mode of the patch-clamp method, we examined the electrical responses of hair cells enzymatically isolated from the goldfish sacculus. 2. Hair cells from the rostral saccule had a short cell body and were ovoidal or eggplantlike in shape, whereas hair cells from the caudal saccule had a variable shape. Many had a longer cell body and were cylindrical or gourd-like in shape, but some short hair cells were also present in the caudal saccule. 3. The short hair cells had a resting potential of about -75 mV. In current-clamp experiments, these hair cells elicited damped oscillatory-potential changes of a relatively small amplitude in response to a depolarizing current. A current in the opposite direction produced a slow hyperpolarization, much larger in amplitude. 4. Resonant frequency of the short, or the oscillatory, type of hair cells ranged from 40 to 200 Hz or higher. However, resonance was generally of a poor quality as compared with that noted for hair cells in the turtle cochlea or frog sacculus. 5. The long hair cells had a resting potential of -90 to -100 mV. In current-clamp experiments, these hair cells elicited an all-or-none spike approximately 50 mV in amplitude in response to a depolarizing current. The spike was usually followed by a plateau, which was maintained for the duration of the depolarizing pulse. In some hair cells, damped slow oscillatory waves were evoked at a rate of 5-15 Hz. On the other hand, a hyperpolarizing current produced potential changes much smaller in amplitude. 6. Voltage-clamp experiments showed that Ca2+-activated K+ channel and A-current, especially its high-threshold subclass, were involved in the generation of outward rectification in the oscillatory-type hair cells. On the other hand, Na+, in addition to Ca2+, was involved in the generation of spike in the spike-type hair cells. Spike potentials were elicited even in the presence of tetrodotoxin (TTX), but the rate of rise was slower as compared with the intact spikes. 7. The spike-type hair cells had an inwardly rectifying K+ channel similar to that noted in the tunicate egg and chick vestibular hair cell. However, the oscillatory-type hair cells had an inwardly rectifying channel similar to the hyperpolarization-activated current, Ih, of the rod inner segment, or sinoatrial nodal cell, or lacked the inwardly rectifying channel. Differences in the resting membrane potential between the oscillatory- and spike-type hair cells are probably related to differences in the inwardly rectifying channels. 8. Effects of sound stimulation were simulated by injecting a half-wave rectified sinusoidal current of various frequencies.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Oncomodulin Is Expressed Exclusively by Outer Hair Cells in the Organ of Corti

1998 ◽  
Vol 46 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Nobuki Sakaguchi ◽  
Michael T. Henzl ◽  
Isolde Thalmann ◽  
Ruediger Thalmann ◽  
Bradley A. Schulte
Keyword(s):  
Hair Cells ◽  
Calcium Binding ◽  
Organ Of Corti ◽  
Ultrastructural Level ◽  
Outer Hair Cells ◽  
Regulatory Function ◽  
Electron Microscopic ◽  
Wide Range ◽  
Intracellular Organelles ◽  
Functional Relevance

Oncomodulin (OM) is a small, acidic calcium-binding protein first discovered in a rat hepatoma and later found in placental cytotrophoblasts, the pre-implantation embryo, and in a wide variety of neoplastic tissues. OM was considered to be exclusively an oncofetal protein until its recent detection in extracts of the adult guinea pig's organ of Corti. Here we report that light and electron microscopic immunostaining of gerbil, rat, and mouse inner ears with a monoclonal antibody against recombinant rat OM localizes the protein exclusively in cochlear outer hair cells (OHCs). At the ultrastructural level, high gold labeling density was seen overlying the nucleus, cytoplasm, and the cuticular plate of gerbil OHCs. Few, if any, gold particles were present over intracellular organelles and the stereocilia. Staining of a wide range of similarly processed gerbil organs failed to detect immunoreactive OM in any other adult tissues. The mammalian genome encodes one α- and one β-isoform of parvalbumin (PV). The widely distributed α PV exhibits a very high affinity for Ca2+ and is believed to serve as a Ca2+ buffer. By contrast, OM, the mammalian β PV, displays a highly attenuated affinity for Ca2+, consistent with a Ca2+-dependent regulatory function. The exclusive association of OM with cochlear OHCs in mature tissues is likely to have functional relevance. Teleological considerations favor its involvement in regulating some aspect of OHC electromotility. Although the fast electromotile response of OHCs does not require Ca2+, its gain and magnitude are modulated by efferent innervation. Therefore, OM may be involved in mediation of intracellular responses to cholinergic stimulation, which are known to be Ca2+ regulated.

Hearing and hair cells

2019 ◽  
pp. 99-131
Author(s):  
Gordon L. Fain
Keyword(s):  
Hair Cells ◽  
Endocochlear Potential ◽  
Outer Hair Cells ◽  
Sensory Transduction ◽  
Basilar Papilla ◽  
Sensory Receptors ◽  
Anatomy And Physiology ◽  
Electrical Resonance ◽  
Present Understanding

“Hearing and hair cells” is the sixth chapter of the book Sensory Transduction and begins with hearing in insects, describing the anatomy and physiology of tympanal organs and Johnston’s organ. It reviews the literature on vertebrate hair cells, which are the sensory receptors of the inner ear. It begins with the anatomy of hair cells and then describes tip links, hair cell transduction proteins, and our present understanding of the nature and identity of the mechanoreceptive channels, including the role of channel gating in bundle stiffness and adaptation of hair cells. A review is given of the anatomy and physiology of the organs of the lateral line, the vestibular system, and the cochlea, together with a description of endolymph and the endocochlear potential, outer hair cells and tuning in mammals, and the role of electrical resonance in tuning in the turtle basilar papilla.

scholarly journals Tamoxifen inhibits BK channels in chick cochlea without alterations in voltage-dependent activation

2009 ◽  
Vol 297 (1) ◽  
pp. C75-C85 ◽  
Author(s):  
Mingjie Tong ◽  
R. Keith Duncan
Keyword(s):  
Hair Cells ◽  
Molecular Mechanisms ◽  
Single Channel ◽  
Frequency Tuning ◽  
Low Frequency ◽  
Bk Channels ◽  
Bk Channel ◽  
Basilar Papilla ◽  
Channel Kinetics ◽  
Open Probability

Large-conductance, Ca2+-activated, and voltage-gated potassium channels (BK, BKCa, or Maxi-K) play an important role in electrical tuning in nonmammalian vertebrate hair cells. Systematic changes in tuning frequency along the tonotopic axis largely result from variations in BK channel kinetics, but the molecular changes underpinning these functional variations remain unknown. Auxiliary β1 have been implicated in low-frequency tuning at the cochlear apex because these subunits dramatically slow channel kinetics. Tamoxifen (Tx), a (xeno)estrogen compound known to activate BK channels through the β-subunit, was used to test for the functional presence of β1. The hypotheses were that Tx would activate the majority of BK channels in hair cells from the cochlear apex due to the presence of β1 and that the level of activation would exhibit a tonotopic gradient following the expression profile of β1. Outside-out patches of BK channels were excised from tall hair cells along the apical half of the chicken basilar papilla. In low-density patches, single-channel conductance was reduced and the averaged open probability was unaffected by Tx. In high-density patches, the amplitude of ensemble-averaged BK current was inhibited, whereas half-activation potential and activation kinetics were unaffected by Tx. In both cases, no tonotopic Tx-dependent activation of channel activity was observed. Therefore, contrary to the hypotheses, electrophysiological assessment suggests that molecular mechanisms other than auxiliary β-subunits are involved in generating a tonotopic distribution of BK channel kinetics and electric tuning in chick basilar papilla.

Tritiated thymidine in the chick embryo inner ear

1989 ◽  
Vol 47 ◽  
pp. 846-847
Author(s):  
Cesar D. Fermin
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
Tritiated Thymidine ◽  
Nerve Fibers ◽  
Basilar Papilla ◽  
Short Exposure ◽  
Short Hair ◽  
Efferent Nerve ◽  
Sensory Epithelia ◽  
Dividing Cells

Development of the chick (Gallus domesticus) inner ear has been studied, and the maturation of cells that detect sound has been analyzed at the E.M. level [1,2,3]. Other workers showed correspondence between ultrastructural maturation and behavioral responses [4,5]. In mammals [6] hair cells mature after ceasation of mitosis {Fig.l}, in a pattern so that older cells are in the base of the cochlea while younger cells are in the apex [7]. But, electrophysiology indicates that cells at the base do not function first. Chicks are precocious with well developed sensory organs at birth, and their embryonic development follows, on a very short time span, a sequence that resembles that of the human ear. This study was undertaken to standarize tritiated thymidine (TT) because resolution of TT in avian embryos differs significantly from mammals [6]. Embryos were injected with 100 μl of TT, and sacrificed 1 or 2 hours later in order to label only those cells that were actively dividing cells at the time of the injection. Specimens were fixed and processed for autoradiography [6].Actively dividing cells incorporate TT after short exposure, with minimal background. It seems that vestibular sensory epithelia {Fig.2} have more dividing cells than the auditory sensory epithelia {Fig.3}, even though the vestibule develop before the cochlea. The ratio between the number of labeled cells over the length of the sensory epithelia is lower in the auditory basilar papilla (0.098 cell/(μm) than in the vestibular utricle (0.77 cell/μm) and saccule (1.66 cell/ μm). When dividing cells were analyzed in the basilar papilla alone, and their distribution displayed along the length of the cochlea over time, older cells were opposite to the VIIIth nerve fibers that innervate those hair cells. A lateral and a longitudinal gradient has been established and hair cells closer to the nerve in the mid-basal area mature earlier than hair cells at both ends of the cochlea [2]. This finding, if occuring in mammals, may explain why mid-frequency are the first to appear [5]. The first 1/3 of the chick cochlea contains mainly short hair cells and are innervated primarily by efferent nerve fibers, which arrive in the cochlea almost a week after the afferent do. Moreover, tall hair cells extend 2/3 of the cochlear length from apex to mid-base and show mature innervation patterns before the short hair cells do. In the short embryonic cochlea, frequencies may be produced first in the what will later be the mid-region because, early in development, that area contains more mature receptors [1,2,3].

scholarly journals The 28-kDa calbindin-D is a major calcium-binding protein in the basilar papilla of the chick.

1988 ◽  
Vol 85 (10) ◽  
pp. 3387-3390 ◽  
Author(s):  
J. C. Oberholtzer ◽  
C. Buettger ◽  
M. C. Summers ◽  
F. M. Matschinsky
Keyword(s):  
Calcium Binding ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Basilar Papilla ◽  
Calbindin D

Further studies on the ultrastructure of the cochlea

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.

Pengaruh sisplatin dosis tinggi terhadap penurunan fungsi sel rambut luar koklea

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.

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