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The frequency-response electroretinogram distinguishes cone and abnormal rod function in rd12 mice.

Dai X, Zhang H, He Y, Qi Y, Chang B, Pang JJ - PLoS ONE (2015)

Bottom Line: Unfortunately, the recorded ERG waveform was difficult to interpret because of a remarkably delayed peak-time, which resembles a rod response more than a cone response.Our results showed that normal rods respond to low frequency flicker (5 and 15 Hz) and that normal cones respond to both low and high frequency flicker (5-35 Hz).It is another simple and valid method for evaluating the respective contributions of retinal rods and cones.

View Article: PubMed Central - PubMed

Affiliation: Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China; Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States of America.

ABSTRACT
Early studies on Rpe65 knockout mice reported that remaining visual function was attributable to cone function. However, this finding has been challenged more and more as time has passed. Electroretinograms (ERGs) showed that rd12 mice, a spontaneous animal model of RPE65 Leber's congenital amaurosis, had sizeable photopic responses. Unfortunately, the recorded ERG waveform was difficult to interpret because of a remarkably delayed peak-time, which resembles a rod response more than a cone response. Here, we compare flicker ERGs in animals with normal rod and cone function (C57BL/6J mice), pure rod function (cpfl5 mice), and pure cone function (Rho(-/-) mice) under different adaptation levels and stimulus intensities. These responses were then compared with those obtained from rd12 mice. Our results showed that normal rods respond to low frequency flicker (5 and 15 Hz) and that normal cones respond to both low and high frequency flicker (5-35 Hz). As was seen in cpfl5 mice, rd12 mice had recordable responses to low frequency flicker (5 and 15Hz), but not to high frequency flicker (25 and 35 Hz). We hypothesize that abnormal rods may be the source of residual vision in rd12 mice, which is proved correct here with double mutant rd12mice. In this study, we show, for the first time, that frequency-response ERGs can effectively distinguish cone- and rod-driven responses in the rd12 mouse. It is another simple and valid method for evaluating the respective contributions of retinal rods and cones.

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Comparison of flicker electroretinograms in all mice strains examined under different adaptation and stimulus intensities.The C57BL/6J mice have normal rod and cone function, the cpfl5 mice have pure rod function, and the Rho-/- mice have pure cone function. Rods respond to low frequency (5 and 15Hz) flicker and cones respond to both low (5 and 15 Hz) and high frequency (25 and 35 Hz) flicker. The rd12 mice only responded to low-frequency flicker. + indicates that flicker ERGs existed,—indicates that flicker ERGs did not exist, 5–35 Hz = flicker frequency.
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pone.0117570.g004: Comparison of flicker electroretinograms in all mice strains examined under different adaptation and stimulus intensities.The C57BL/6J mice have normal rod and cone function, the cpfl5 mice have pure rod function, and the Rho-/- mice have pure cone function. Rods respond to low frequency (5 and 15Hz) flicker and cones respond to both low (5 and 15 Hz) and high frequency (25 and 35 Hz) flicker. The rd12 mice only responded to low-frequency flicker. + indicates that flicker ERGs existed,—indicates that flicker ERGs did not exist, 5–35 Hz = flicker frequency.

Mentions: Comparing and contrasting flicker ERGs in the four strains of mice (Fig. 4) revealed that rd12 mice (Rpe65 natural deficiency) lost their high frequency flicker response, which resembled rod-driven responses observed in cpfl5 mice and scotopic (rod) flicker ERGs in C57BL/6J mice.


The frequency-response electroretinogram distinguishes cone and abnormal rod function in rd12 mice.

Dai X, Zhang H, He Y, Qi Y, Chang B, Pang JJ - PLoS ONE (2015)

Comparison of flicker electroretinograms in all mice strains examined under different adaptation and stimulus intensities.The C57BL/6J mice have normal rod and cone function, the cpfl5 mice have pure rod function, and the Rho-/- mice have pure cone function. Rods respond to low frequency (5 and 15Hz) flicker and cones respond to both low (5 and 15 Hz) and high frequency (25 and 35 Hz) flicker. The rd12 mice only responded to low-frequency flicker. + indicates that flicker ERGs existed,—indicates that flicker ERGs did not exist, 5–35 Hz = flicker frequency.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4338143&req=5

pone.0117570.g004: Comparison of flicker electroretinograms in all mice strains examined under different adaptation and stimulus intensities.The C57BL/6J mice have normal rod and cone function, the cpfl5 mice have pure rod function, and the Rho-/- mice have pure cone function. Rods respond to low frequency (5 and 15Hz) flicker and cones respond to both low (5 and 15 Hz) and high frequency (25 and 35 Hz) flicker. The rd12 mice only responded to low-frequency flicker. + indicates that flicker ERGs existed,—indicates that flicker ERGs did not exist, 5–35 Hz = flicker frequency.
Mentions: Comparing and contrasting flicker ERGs in the four strains of mice (Fig. 4) revealed that rd12 mice (Rpe65 natural deficiency) lost their high frequency flicker response, which resembled rod-driven responses observed in cpfl5 mice and scotopic (rod) flicker ERGs in C57BL/6J mice.

Bottom Line: Unfortunately, the recorded ERG waveform was difficult to interpret because of a remarkably delayed peak-time, which resembles a rod response more than a cone response.Our results showed that normal rods respond to low frequency flicker (5 and 15 Hz) and that normal cones respond to both low and high frequency flicker (5-35 Hz).It is another simple and valid method for evaluating the respective contributions of retinal rods and cones.

View Article: PubMed Central - PubMed

Affiliation: Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China; Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States of America.

ABSTRACT
Early studies on Rpe65 knockout mice reported that remaining visual function was attributable to cone function. However, this finding has been challenged more and more as time has passed. Electroretinograms (ERGs) showed that rd12 mice, a spontaneous animal model of RPE65 Leber's congenital amaurosis, had sizeable photopic responses. Unfortunately, the recorded ERG waveform was difficult to interpret because of a remarkably delayed peak-time, which resembles a rod response more than a cone response. Here, we compare flicker ERGs in animals with normal rod and cone function (C57BL/6J mice), pure rod function (cpfl5 mice), and pure cone function (Rho(-/-) mice) under different adaptation levels and stimulus intensities. These responses were then compared with those obtained from rd12 mice. Our results showed that normal rods respond to low frequency flicker (5 and 15 Hz) and that normal cones respond to both low and high frequency flicker (5-35 Hz). As was seen in cpfl5 mice, rd12 mice had recordable responses to low frequency flicker (5 and 15Hz), but not to high frequency flicker (25 and 35 Hz). We hypothesize that abnormal rods may be the source of residual vision in rd12 mice, which is proved correct here with double mutant rd12mice. In this study, we show, for the first time, that frequency-response ERGs can effectively distinguish cone- and rod-driven responses in the rd12 mouse. It is another simple and valid method for evaluating the respective contributions of retinal rods and cones.

Show MeSH
Related in: MedlinePlus