Motile responses of cochlear outer hair cells stimulated with an alternating electrical field

Kitani, Rei; Kakehata, Seiji; Kalinec, Federico

doi:10.1016/j.heares.2011.05.013

Cited by 9 publications

(18 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(C) When the OHC in B was stimulated with an EAEF parallel to its longitudinal axis, robust changes in L 1 length (amplitude~1 mm, red trace) were observed as we monitored the electrical signal cycle by cycle. This change of~2.5% of the L 1 total length (~39.5 mm) is identical to the typical electromotile amplitude of OHCs exposed to an EAEF (28). In contrast, no changes in L 2 (green trace) were observed in the Deiters cell shown in B for any orientation of the EAEF.…”

Section: Figure 1 Ms Are Reliable Indicators Of Ohc Motility (A) Schsupporting

confidence: 69%

“…Temporal bones were obtained from young albino guinea pigs (Cavia porcellus, 200-300 g) of either sex, euthanized with CO 2 according to procedures approved by House Research Institute's Institutional Animal Care and Use Committee. OHCs, isolated as described in the literature (27,28), were transferred to glass-bottomed experimental dishes containing L-15 medium with 25 mM HEPES (Sigma, St. Louis, MO), observed with Nomarski differential interference contrast (DIC) optics on an Axiovert 135TV inverted microscope with a 63Â/1.2 C-Apochromat objective (Zeiss, Thornwood, NY), and used within 2 h after isolation. Osmolarity was measured with a freezing-point osmometer (mOsmette 5004, Precision Systems, Natick, MA), and adjusted to 305-310 mOsm with D-glucose or distilled water.…”

Section: Isolation Of Ohcsmentioning

confidence: 99%

“…In previous publications, we provided a general description of OHC motility in response to osmotic challenges (25,26) and electrical stimulation (25)(26)(27)(28). Here, we use polystyrene and carboxylated microspheres (MS) as membrane markers and high-speed video recording to perform a detailed analysis of the local responses of the lateral wall of electrically and osmotically stimulated OHCs.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Microdomains Shift and Rotate in the Lateral Wall of Cochlear Outer Hair Cells

Kitani

Park

Kalinec

2013

Biophysical Journal

Self Cite

View full text Add to dashboard Cite

Outer hair cell (OHC) electromotility, a response consisting of reversible changes in cell length and diameter induced by electrical stimulation, confers remarkable sensitivity and frequency resolution to the mammalian inner ear. Looking for a better understanding of this mechanism, we labeled isolated guinea pig OHCs with microspheres and, using high-speed video recording, investigated their movements at the apical, mid, and basal regions of osmotically and electrically stimulated cells. After hypoosmotic challenge, OHCs shortened and their diameter increased, with microspheres moving always toward the central plane; iso-osmolarity returned OHCs to their original shape and microspheres to their original positions. Under electrical stimulation, microspheres exhibited robust movements, with their displacement vectors changing in direction from random to parallel to the longitudinal axis of the cells with peak reorientation speeds of up to 6 rad/s and returning to random after 5 min without stimulation. Alterations in plasma-membrane cholesterol levels as well as cytoskeleton integrity affected microsphere responses. We concluded that microspheres attach to different molecular microdomains, and these microdomains are able to shift and rotate in the plane of the OHC lateral wall with a dynamics tightly regulated by membrane lipid composition and the cortical cytoskeleton.

show abstract

Section: Figure 1 Ms Are Reliable Indicators Of Ohc Motility (A) Schsupporting

confidence: 69%

Section: Isolation Of Ohcsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microdomains Shift and Rotate in the Lateral Wall of Cochlear Outer Hair Cells

Kitani

Park

Kalinec

2013

Biophysical Journal

Self Cite

View full text Add to dashboard Cite

show abstract

“…The past decade has brought remarkable advances in the understanding of the micromechanics of the auditory system and its components (Barral and Martin 2011;Brownell et al 2011;Cheatham and Dallos 2000;Dong and Olson 2009;Eiber 2008;Elliott et al 2007Elliott et al , 2011Eze and Olson 2011;Fettiplace 2006;Fisher et al 2012;Gao et al 2013;Gavara and Chadwick 2009;Gavara et al 2011;Gu et al 2008;He et al 2008;Hemila et al 2010;Hong and Freeman 2006;Jacob et al 2009;Kapadia and Lutman 2000;Kitani et al 2011;Kolston 2000;Grosh 2011, Meaud andGrosh 2010;Naidu and Mountain 2007;Nam and Fettiplace 2012;Ren and Nuttall 2000;Rhode 2007;Santos-Sacchi 2008;Van Dijk et al 2011;Zhang et al 2007;Zheng et al 2007). Quantitative descriptions of basilar membrane motion patterns are available for the base and the apex of the mammalian cochlea (e.g., Olson et al 2012;Robles and Ruggero 2001).…”

Section: Introductionmentioning

confidence: 99%

Basilar Membrane and Tectorial Membrane Stiffness in the CBA/CaJ Mouse

Teudt

Richter

2014

JARO

View full text Add to dashboard Cite

The mouse has become an important animal model in understanding cochlear function. Structures, such as the tectorial membrane or hair cells, have been changed by gene manipulation, and the resulting effect on cochlear function has been studied. To contrast those findings, physical properties of the basilar membrane (BM) and tectorial membrane (TM) in mice without gene mutation are of great importance. Using the hemicochlea of CBA/CaJ mice, we have demonstrated that tectorial membrane (TM) and basilar membrane (BM) revealed a stiffness gradient along the cochlea. While a simple spring mass resonator predicts the change in the characteristic frequency of the BM, the spring mass model does not predict the frequency change along the TM. Plateau stiffness values of the TM were 0.6±0.5, 0.2± 0.1, and 0.09±0.09 N/m for the basal, middle, and upper turns, respectively. The BM plateau stiffness values were 3.7±2.2, 1.2±1.2, and 0.5±0.5 N/m for the basal, middle, and upper turns, respectively. Estimations of the TM Young's modulus (in kPa) revealed 24.3±25.2 for the basal turns, 5.1±4.5 for the middle turns, and 1.9±1.6 for the apical turns. Young's modulus determined at the BM pectinate zone was 76.8±72, 23.9±30.6, and 9.4±6.2 kPa for the basal, middle, and apical turns, respectively. The reported stiffness values of the CBA/CaJ mouse TM and BM provide basic data for the physical properties of its organ of Corti.

show abstract

“…These layers of OHCs' lateral wall are connected together by "pillars" that play a role in the interaction between the plasma membrane and cytoskeleton (cortical lattice) [7,39]. OHC electromotility is variable by many factors; intracellular turgor pressure, osmolarity, temperature, electrical field, drugs, and so on [17,18,23].…”

Section: Introductionmentioning

confidence: 99%

Effects of cholesterol alterations are mediated via G-protein-related pathways in outer hair cells

Nagaki

Kakehata

Kitani

et al. 2013

Pflugers Arch - Eur J Physiol

Self Cite

View full text Add to dashboard Cite

Cholesterol is an essential component of cell membranes, and determines their rigidity and fluidity. Alterations in membrane cholesterol by MβCD or water-soluble cholesterol affect the stiffness, capacitance, motility, and cell length of outer hair cells (OHCs). This suggests that reconstruction of the cytoskeleton may be induced by cholesterol alterations. In this study, we investigated intracellular signaling pathways involving G proteins to determine whether they modulate the changes in voltage-dependent capacitance caused by cholesterol alterations. Membrane capacitance of isolated guinea pig OHCs were assessed using a two-sine voltage stimulus protocol superimposed onto a voltage ramp (200 ms duration) from −150 to +140 mV. One group of OHCs was treated with 100 μM guanosine 5′-O-(3-thiotriphosphate) tetralithium salt (GTPγS), the GTP analog, administrated into individual cells via patch pipettes. Another group of OHCs was internally perfused with 600 μM guanosine 5′-(β-thio) diphosphate trilithium salt (GDPβS), the GDP analog. A third group was perfused with internal solution only as a control. Application of 1 mM MβCD shifted non-linear capacitance curves to the depolarized direction of the control group with reduction of the peak capacitance (C mpeak ). After the 10-min application of MβCD, shifts of voltage at C mpeak (V cmpeak ) and reduction of C mpeak were 73.32±11.09 mV and 9.09±2.10 pF, respectively (n=4). On the other hand, in the GTPγS-treated group, the shift of V cmpeak and reduction of C mpeak were attenuated remarkably. The shift of V cmpeak and reduction of C mpeak in the 10-min application of MβCD were 9.73± 10.92 mV and 3.08±1.91 pF, respectively (n=7). MβCD decreased the cell length by 16.53±4.27 % in the control group and by 6.45±6.22 % in the GTPγS group. In addition, we investigated the effects of GDPβS on cholesteroltreated OHCs. One millimolar cholesterol was externally applied after the 4-min application of 1 mM MβCD because the shift of V-C m function caused by cholesterol alone was small. Application of cholesterol shifted V-C m curves of the control group to the hyperpolarized direction with increase of the C mpeak . After the 10-min application of cholesterol, changes of V cmpeak and C mpeak were −9.19±6.68 mV and 2.14±0.44 pF, respectively (n=4). On the other hand, in the GDPβS-treated OHCs, the shift of V cmpeak and increase of C mpeak were attenuated markedly. The shift of V cmpeak and increase of C mpeak after 10 min were 5.13±10.46 mV and −0.55±1.39 pF, respectively (n=6). This study demonstrated that internally perfused GTPγS inhibited the MβCD effects and GDPβS inhibited the cholesterol effects, raising the possibility that G proteins may be involved in outer hair cell homeostasis as well as the possibility that cholesterol response may be G protein mediated. More study is required to clarify the detailed role of G proteins in the relation between cholesterol and the OHC cytoskeleton.

show abstract

Motile responses of cochlear outer hair cells stimulated with an alternating electrical field

Cited by 9 publications

References 43 publications

Microdomains Shift and Rotate in the Lateral Wall of Cochlear Outer Hair Cells

Microdomains Shift and Rotate in the Lateral Wall of Cochlear Outer Hair Cells

Basilar Membrane and Tectorial Membrane Stiffness in the CBA/CaJ Mouse

Effects of cholesterol alterations are mediated via G-protein-related pathways in outer hair cells

Contact Info

Product

Resources

About