Hypotonic swelling of salicylate-treated cochlear outer hair cells

Hear Res. 2007 Jun;228(1-2):95-104. doi: 10.1016/j.heares.2007.02.007. Epub 2007 Mar 1.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cell Membrane Permeability / drug effects
  • Cell Size / drug effects*
  • Cells, Cultured
  • Guinea Pigs
  • Hair Cells, Auditory, Outer / drug effects*
  • Hair Cells, Auditory, Outer / metabolism
  • Hypotonic Solutions / metabolism
  • Isotonic Solutions / metabolism
  • Ketoglutaric Acids / pharmacology
  • Models, Biological
  • Osmolar Concentration
  • Osmosis / drug effects
  • Sodium Chloride / metabolism
  • Sodium Salicylate / pharmacology*
  • Water / metabolism

Substances

  • Hypotonic Solutions
  • Isotonic Solutions
  • Ketoglutaric Acids
  • Water
  • Sodium Chloride
  • Sodium Salicylate