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S. Nymark, P. Kärkäs, A. Koskelainen; Cone ERG Photoresponses From the Isolated Mouse Retina . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3088.
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© ARVO (1962-2015); The Authors (2016-present)
To record mouse cone photoresponses by the electroretinogram (ERG) technique and compare them with suction pipette data from single cones in the literature.
Pure aspartate–isolated cone photoresponses to flashes of light were obtained at 36 °C by the double–flash ERG technique across isolated mouse (Mus musculus) retinas. The first flash (544 nm) was chosen to saturate rods; the second flash (503 nm, 1.4 ms) 1–1.5 s later was used to elicit pure cone photoresponses. Half–saturating light intensities of cones were determined from five–point intensity–response data.
The mean amplitude of saturated cone responses was 15 ± 4 % (mean ± SEM) of the saturated rod response. The time–to–peak (tp) of the dim–flash response was 63 ± 7 ms and the half–saturating flash intensity (I1/2) was 2 800 ± 600 photons µm–2. The corresponding values from suction pipette recordings of WT mice cones are tp = 80 ± 10 ms and I½ = 8 200 ± 3 300 photons µm–2 (UV–light), respectively (Nikonov et al. 2005, Invest. Ophthalmol. Vis. Sci. 46: E–Abstract 4634).
Our mouse cone ERG photoresponses are somewhat faster than responses obtained by suction pipette recordings from single cells. This is in a qualitative agreement with rod data (tp = 140 ms from our unpublished mouse rod ERG compared with tp = 210 ms from the single rod recordings by Nikonov et al. 2005). The half–saturating flash intensities are comparable if we take into account the sensitivity difference of mouse cones to UV and middle–wavelength light as well as the differences in measurement techniques.
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