Fig. 4. Effect of dopamine (0.1, 0.5, 1.0, 10 µmol l^-1) on LC opsin mRNA expression in the morning (A) and in the evening (B). In the morning, dopamine increased LC opsin mRNA expression. In the evening, there was a tendency of increase, but it was not statistically significant. Data represent the mean ± S.E.M. (N=16). ^*P<0.01; NS, not significant.