Ultraviolet and middle wavelength sensitive cone responses in the electroretinogram (ERG) of normal and Rpe65 -/- mice.
Ultra-violet (UV) and middle wavelength sensitive (M) cone responses were identified in the ERG of normal and Rpe65 -/- mice using chromatic flashes and selective chromatic adaptation. In normal mice, the UV-cone response was as large as, or larger, in the presence of a bright yellow adapting light than it is in the presence of a dim white light. The M-cone response became undetectable in the presence of the yellow adapting light. Yellow adapting light initially reduced the UV response, but it recovered in 8-10 min. The M-cone response did not recover. UV-cone responses were undetectable in Rpe65 -/- mice. The M-cone response of young Rpe65 -/- mice was almost as large as in normal mice. A yellow adapting light only diminished this M-cone response. With age, the M-cone response further decreased in Rpe -/- mice. We show a pronounced loss of UV-cone function in Rpe65 -/- mice, which may be related to a defect UV-cones share with rods. The M-cone function is also affected already in young Rpe65 -/- mice. The transient effect of a yellow adapting light on the UV-cone response of normal mice is suggested to be neural, because it disappears during maintained light adaptation.
Ekesten
B
B
Unit for Ophthalmology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Gouras
P
P
Salchow
D J
DJ
D000221:Adaptation, Ocular / Q000502:physiology; D000818:Animals; D004596:Electroretinography; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D012162:Retinal Degeneration / Q000503:physiopathology*; D013053:Spectrophotometry; D018709:Statistics, Nonparametric; D014466:Ultraviolet Rays