3.1 Chronic caffeine treatment extended circadian activity
period in WT.
We administered 0.05% caffeine to WT (n=7) under LD. After 7 days, the
caffeine-treated and control (n=6) mice were moved to DD. For 21 days in
DD, the activity period of
caffeine-treated mice (23.85±0.022 h, Figure 1a) was longer than that of
controls (23.72±0.032 h, Figure 1b). After replacing caffeine by water,
the period did not shorten for 26
days, and caffeine re-administration for 21 days
extended this period
(Figure 1a, 1c upper, one-way
ANOVA P=0.008). In the control mice, caffeine administration was started
at day 21 in DD. Caffeine treatment for 26 days extended the period, as
previously reported (Oike et al., 2011). After replacing caffeine by
water, the period did not shorten for the following 21 days (Figure 1b,
1c lower, one-way ANOVA, P=0.003).