Measurements and a model of the outer hair cell hydraulic conductivity

Ratnanather, J. Tilak; Zhi, Man; Brownell, William E.; Popel, Aleksander S.

doi:10.1016/0378-5955(96)00014-7

Cited by 14 publications

(24 citation statements)

References 15 publications

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“…The initial length for untreated cells is slightly different from that reported in Ratnanather et al (1996b) because a different reference point was used.…”

Section: Results and Analysismentioning

confidence: 94%

“…We have previously shown that osmotic-induced OHC volume change can be described by (Ratnanather et al, 1996b)…”

Section: Results and Analysismentioning

confidence: 99%

“…Shaded boxes indicate duration of perfusion of the different solutions (isotonic and hypotonic solutions); note the dead time of approximately 210 s. of perfusion of the hypotonic solution). Superimposed on each graph is the response of untreated OHCs to hypotonic solutions; the DC = À45 mOsm data for untreated OHCs was previously reported (Ratnanather et al, 1996b).…”

Section: Discussionmentioning

confidence: 99%

“…The OHC hydraulic conductivity (P f ), which is a measure of the rate at which water crosses the OHC wall, may be obtained by analyzing OHC shape changes in response to an osmotic challenge. We have analyzed the OHC volume response to a hypotonic solution with an osmotic difference of À45 mOsm and obtained P f = 3 · 10 À4 cm/s for the OHC hydraulic conductivity using a mathematical model of osmotic water transport (Ratnanather et al, 1996b). This value is on the low side of values reported for different lipid bilayers and is two orders of magnitude lower than the hydraulic conductivity of red blood cells.…”

Section: Introductionmentioning

confidence: 97%

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Hypotonic swelling of salicylate-treated cochlear outer hair cells

et al. 2007

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The outer hair cell (OHC) is a hydrostat with a low hydraulic conductivity of Pf=3x10(-4) cm/s across the plasma membrane (PM) and subsurface cisterna that make up the OHC's lateral wall. The SSC is structurally and functionally a transport barrier in normal cells that is known to be disrupted by salicylate. The effect of sodium salicylate on Pf is determined from osmotic experiments in which isolated, control and salicylate-treated OHCs were exposed to hypotonic solutions in a constant flow chamber. The value of Pf=3.5+/-0.5x10(-4) cm/s (mean+/-s.e.m., n=34) for salicylate-treated OHCs was not significantly different from Pf=2.4+/-0.3x10(-4) cm/s (mean+/-s.e.m., n=31) for untreated OHCs (p=.3302). Thus Pf is determined by the PM and is unaffected by salicylate treatment. The ratio of longitudinal strain to radial strain epsilonz/epsilonc=-0.76 for salicylate-treated OHCs was significantly smaller (p=.0143) from -0.72 for untreated OHCs, and is also independent of the magnitude of the applied osmotic challenge. Salicylate-treated OHCs took longer to attain a steady-state volume which is larger than that for untreated OHCs and increased in volume by 8-15% prior to hypotonic perfusion unlike sodium alpha-ketoglutarate-treated OHCs. It is suggested that depolymerization of cytoskeletal proteins and/or glycogen may be responsible for the large volume increase in salicylate-treated OHCs as well as the different responses to different modes of application of the hypotonic solution.

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“…The initial length for untreated cells is slightly different from that reported in Ratnanather et al (1996b) because a different reference point was used.…”

Section: Results and Analysismentioning

confidence: 94%

“…We have previously shown that osmotic-induced OHC volume change can be described by (Ratnanather et al, 1996b)…”

Section: Results and Analysismentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

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Hypotonic swelling of salicylate-treated cochlear outer hair cells

et al. 2007

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“…We expected the RVD effect in our experiments to be insignificant because swelling duration did not exceed 25 sec. Our sensitive motion detection method also allowed us to minimize the degree of swelling by using a hypo-osmotic challenge of only Ϫ5 mOsm/kg as compared with the previously used Ϫ25 and Ϫ45 mOsm/kg (Crist et al, 1993;Ratnanather et al, 1996). The smaller volume changes reduced the potential interference of swellingactivated osmolyte flow.…”

Section: Osmotic Water Permeability Of Ohcsmentioning

confidence: 99%

Water Permeability of Cochlear Outer Hair Cells: Characterization and Relationship to Electromotility

et al. 2000

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The distinguishing feature of the mammalian outer hair cells (OHCs) is to elongate and shorten at acoustic frequencies, when their intracellular potential is changed. This "electromotility" or "electromechanics" depends critically on positive intracellular pressure (turgor), maintained by the inflow of water through yet uncharacterized water pathways. We measured the water volume flow, J v , across the plasma membrane of isolated guinea pig and rat OHCs after osmotic challenges and estimated the osmotic water permeability coefficient, P f , to be ϳ10 Ϫ 2 cm/sec. This value is within the range reported for osmotic flow mediated by the water channel proteins, aquaporins. J v was inhibited by HgCl 2 , which is known to block aquaporin-mediated water transport. P f values that were estimated for OHCs from neonatal rats were of the order of ϳ2ϫ10 Ϫ 3 cm/sec, equivalent to that of membranes lacking water channel proteins. In an immunofluorescence assay we showed that an anti-peptide antibody specific for aquaporins labels the lateral plasma membrane of the OHC in the region in which electromotility is generated. Using patch-clamp recording, we found that water influx into the OHC is regulated by intracellular voltage. We also found that the most pronounced increases of the electromotility-associated charge movement and of the expression of OHC water channels occur between postnatal days 8 and 12, preceding the onset of hearing function in the rat. Our data indicate that electromotility and water transport in OHCs may influence each other structurally and functionally.

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The Piezoelectric Outer Hair Cell

Brownell

Vertebrate Hair Cells

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Measurements and a model of the outer hair cell hydraulic conductivity

Cited by 14 publications

References 15 publications

Hypotonic swelling of salicylate-treated cochlear outer hair cells

Hypotonic swelling of salicylate-treated cochlear outer hair cells

Water Permeability of Cochlear Outer Hair Cells: Characterization and Relationship to Electromotility

The Piezoelectric Outer Hair Cell

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