Purchase this article with an account.
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/.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To study the characteristics of dark-adapted and light adapted intensity-response functions in mice, rats and monkeys recorded under similar conditions.
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.
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.
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.
This PDF is available to Subscribers Only