May 2008
Volume 49, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2008
Dark- and Light-Adapted Intensity-Response Function ERG Characteristics in Rodents and Monkeys
Author Affiliations & Notes
  • R. T. Tzekov
    Acucela Inc, Bothell, Washington
  • M. Gibson
    Acucela Inc, Bothell, Washington
  • L. Zhu
    Acucela Inc, Bothell, Washington
  • A. Fawzi
    Acucela Inc, Bothell, Washington
  • R. Kubota
    Acucela Inc, Bothell, Washington
  • Footnotes
    Commercial Relationships  R.T. Tzekov, E, E; M. Gibson, E, E; L. Zhu, E, E; A. Fawzi, E, E; R. Kubota, E, E.
  • Footnotes
    Support  None.
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 5814. doi:https://doi.org/
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      R. T. Tzekov, M. Gibson, L. Zhu, A. Fawzi, R. Kubota; Dark- and Light-Adapted Intensity-Response Function ERG Characteristics in Rodents and Monkeys. Invest. Ophthalmol. Vis. Sci. 2008;49(13):5814. doi: https://doi.org/.

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

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Abstract

Purpose: : To study the characteristics of dark-adapted and light adapted intensity-response functions in mice, rats and monkeys recorded under similar conditions.

Methods: : A total of 28 albino (BALB/c), 6 pigmented (C57CL/6) mice, 2 albino rats and 12 cynomolgus monkeys were tested under similar dark and light-adapted conditions and similar series of light intensities. Scotopic sensitivity (a- and b-wave amplitude) was evaluated by applying 14-15 luminance steps stimuli (0.00003 to 333 cd.s/m²) and photopic ERG (b-wave amplitude) was recorded after 10 min light adaptation by applying 9 -10 stimuli (0.3 to 333 cd.s/m²). Oscillatory potentials were removed using digital filtration from all traces.

Results: : For all species, the dark-adapted intensity response b-wave amplitude function had 2 characteristics parts: an initial part, spanning 4 log units and a second part, covering 3 log units. Both parts could be fitted well with a sigmoidal function, but differed in top to bottom range, slope and variability. Fitting of the a-wave function demonstrated similar slope compared to the initial part of the b-wave. The light-adapted b-wave function fitted well through the full range of intensities for rodents, but only to ~30 cd.s/m² in monkeys ("photopic hill" phenomenon). Additionally, the Hill slope of the function was steeper in monkeys compared to rodents.

Conclusions: : A- and b-wave ERG amplitudes were fitted well with sigmoidal type (Naka-Rushton) functions over a large range of stimulus intensities. The fitting parameters were similar between species for scotopic responses, but differed for photopic responses, reflecting differences in cell populations and topography.

Keywords: electroretinography: non-clinical • electrophysiology: non-clinical • retina 
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