Physiological function of S-cone system is not enhanced in rd7 mice.
The rd7mouse is a mutant mouse with a relatively late development of retinal degeneration. Earlier studies have shown that rd7 mice have a distinctive pattern of retinal dysplasia with an increased number of cone cells, particularly those with S (short wavelength)-opsin immunoreactivity. These alterations of the rd7 retina are caused by a mutation in the photoreceptor cell-specific nuclear receptor gene, Nr2e3, which is involved in the signaling pathway regulating photoreceptor cell differentiation, cell maintenance, and cell-cell interactions. The purpose of this study was to determine the physiological properties of the rd7 retina using electroretinographic (ERG) techniques. We found that the maximal a-wave amplitude of the ERG in rd7 mice was already reduced to half of the congenic controls at 6 weeks of age with normal phototransduction sensitivity. The photopic ERGs of rd7 mice were not supernormal, and the amplitudes of the S-cone ERGs were not significantly different from those recorded in controls. These results suggested that even though the number of cones expressing S-opsin is increased, the physiological function of the S-cone system is not enhanced in rd7 mice.
Ueno
Shinji
S
Department of Ophthalmology, Nagoya University School of Medicine, 65 Tsuruma-cho, Showa-ku, Nagoya 466-8550, Japan.
Kondo
Mineo
M
Miyata
Kentaro
K
Hirai
Toshie
T
Miyata
Takaki
T
Usukura
Jiro
J
Nishizawa
Yuji
Y
Miyake
Yozo
Y
D000818:Animals; D003623:Dark Adaptation; D004596:Electroretinography; D005136:Eye Proteins / Q000235:genetics; D005838:Genotype; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009154:Mutation; D057093:Orphan Nuclear Receptors; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics*; D017949:Retinal Cone Photoreceptor Cells / Q000503:physiopathology*; D012162:Retinal Degeneration / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D017299:Rod Opsins / Q000378:metabolism; D014785:Vision, Ocular
D005136:Eye Proteins; C485736:Nr2e3 protein, mouse; D057093:Orphan Nuclear Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D017299:Rod Opsins