Ultraviolet light-induced and green light-induced transient pupillary light reflex in mice.
OBJECTIVE
To study UV light-induced and green light-induced pupillary light reflex (PLR) in mice and to measure the illumination thresholds of rod-mediated and cone-mediated PLR responses.


METHODS
We measured dark-adapted transient PLR- in C57BL/6 mice elicited with ultraviolet and green light over an intensity range of 9 log units. To assist in isolating the responses mediated by rods and cones, we studied the PLRs in mouse models presenting pure cone and pure rod functions. We also characterized ERG signals in these mice under the same experimental conditions.


RESULTS
The UV light-induced transient PLR has identical intensity-response curves as green light-induced PLR in all the three mice strains. The threshold (5% PLR) of rod-driven PLR is 107 approximately 108 photons cm2 s-1, which is 1 approximately 2 log units lower than the dark-adapted ERG b-wave. The threshold of cone-driven PLR is approximately 1012.5 photons cm-2 s-1 and is similar to that of the cone ERG.


CONCLUSIONS
We demonstrated that mice have PLR responses under UV stimulation. The cone-elicited PLRs have a threshold that is approximately 5 log units higher than that of rod-elicited PLR at both UV and green wavelengths. We observed a divergence between the spectra responses in PLR and ERG. However, the mechanism and implications of this phenomenon are yet to be identified.
Yao
Gang
G
Department of Biological Engineering, University of Missouri Columbia, Columbia, MO 65211-0001, USA.
Zhang
Keqing
K
Bellassai
Matthew
M
Chang
Bo
B
Lei
Bo
B
D000818:Animals; D003623:Dark Adaptation; D004596:Electroretinography; D008027:Light; D051379:Mice; D008810:Mice, Inbred C57BL; D010775:Photic Stimulation; D012025:Reflex, Pupillary / Q000528:radiation effects*; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology / Q000528:radiation effects; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology / Q000528:radiation effects; D012684:Sensory Thresholds; D014466:Ultraviolet Rays