May 1994
Volume 35, Issue 6
Free
Articles  |   May 1994
Mathematical model of TMA+ diffusion and prediction of light-dependent subretinal hydration in chick retina.
Author Affiliations
  • V I Govardovskii
    Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg.
  • J D Li
    Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg.
  • A V Dmitriev
    Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg.
  • R H Steinberg
    Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg.
Investigative Ophthalmology & Visual Science May 1994, Vol.35, 2712-2724. doi:
  • Views
  • PDF
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      V I Govardovskii, J D Li, A V Dmitriev, R H Steinberg; Mathematical model of TMA+ diffusion and prediction of light-dependent subretinal hydration in chick retina.. Invest. Ophthalmol. Vis. Sci. 1994;35(6):2712-2724.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

PURPOSE: To derive a mathematical model of TMA+ diffusion across the retina that can be used to estimate the amplitude and kinetics of the light-evoked increase in subretinal hydration and its effect on the concentration of other ions. METHODS: All experimental data were obtained in chick retina-pigment epithelium-choroid preparations as described in the accompanying paper. RESULTS: Diffusional properties of the retina were derived from the time course of [TMA+]o in the subretinal space (SRS) after changes in the retinal perfusate. Then, the SRS volume changes underlying the light-induced [TMA+]o response can be derived using a mathematical model of TMA+ diffusion. Complete retinal depth series of light-evoked [TMA+]o responses could be simulated by producing a corresponding expansion of the SRS. Volume changes inferred from the diffusion model were 2.2 to 3.8 times larger and more prolonged than could be derived directly from delta [TMA+]o. The model predicted up to a 20% peak increase in subretinal-space hydration during illumination. The effects of this volume increase on subretinal K+ and Ca2+ were estimated. These predictions were supported by inhibiting the volume increase with DIDS, which blocks retinal pigment epithelium basal membrane Cl- conductance. CONCLUSIONS: The primary source of light-evoked changes in extracellular TMA+ concentration recorded throughout the retina is an increase in hydration (volume) of the subretinal space. The response spreads to the inner retina by diffusion. Effects of TMA+ diffusion lead to large underestimates of the underlying volume changes. The light-evoked volume change alters the composition of the subretinal space and light-induced responses of other ions.

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×