Fig. 2. Circadian rhythms of LC opsin mRNA expression under different lighting conditions. In LD, the expression of LC opsin mRNA was low in the morning and high in the afternoon. The fluctuation of LC opsin mRNA persisted in DD (A) or LL (B) for only one day. In the second day of DD or LL, the expression became flat. Horizontal bars at the top of the figure indicate lighting conditions in the day and night; white bar, day; black bars, night; gray bars, subjective days without light; hatched bars, subjective night with light. Data represent the mean ± S.E.M. (N=16).