Figure 5. Effect of NBTI and taurine on light-dark difference in AANAT activity

Cultures were prepared from embryonic day 6 retinas and incubated as described in the legend to Figure 1, with complete replacement of the culture medium on DIV 4, except that either 5 μM NBTI or 5 mM taurine was added on DIV 1 and 4. Cells were harvested on DIV 6 at ZT 10 and ZT 18. Data are shown as means with the error bars representing the SEM (N=5). In taurine-treated cells, AANAT activity was significantly higher in darkness than in light (*p <0.001). AANAT activity of NBTI-treated cells in darkness was higher than that in light-exposed NBTI-treated cells (**p <0.001) and also higher than that in taurine-treated cells in darkness (p=0.038).