Figure 8  Electroretinograms from 6-Mo-Old RanBP2+/−and RanBP2+/+ Inbred Mice Showing Photoreceptor and Postreceptor Neuron Electrophysiological Response Phenotypes
(A) Scotopic (dark-adapted) responses from RanBP2+/− mice to light stimuli of increasing intensity, beginning at threshold, have reduced amplitudes compared to those observed in RanBP2+/+ mice. The three lower intensities represent responses generated in the rod photoreceptor neuronal pathway. The upper intensities are comprised of responses generated in both the rod and cone pathways.
(B) Photopic (light-adapted, cone photoreceptor pathway) responses of RanBP2+/− mice to increasing light stimulus intensities also exhibited reduced amplitudes compared to those observed in RanBP2+/+ mice.
(C) Average ± SE (n = 9) scotopic b-wave amplitudes from RanBP2+/− (open circles) and RanBP2+/+ (filled squares) mice representing postreceptoral neuron function. (Note: log amplitude scale.)
(D) Average ± SE (n = 5) scotopic a-wave amplitudes, representing photoreceptor function, for RanBP2+/− and RanBP2+/+ mice in response to bright flashes. Amplitudes of responses from RanBP2+/− mice were lower over the entire range of stimulus intensities for both b- and a-waves. Asterisks represent significant differences between the groups (Student's t test, p < 0.05). Statistical significance was found across all intensities for b-wave amplitudes (2-way ANOVA, p < 0.0001), but not for the a-wave.