Fig. 4.
Effects of chronic caffeine intake on LA and oxygen consumption (O2C) in mice. After the baseline recording (Water), mice drank tap water with 0.3 g/l caffeine for 7 days (Caffeine). The LAs in the water group are shown as 5-day averages in 30-min intervals, whereas LA data in caffeine group are shown as 3-day averages (days 5, 6, and 7 during chronic caffeine treatment). O2C is shown as 1-h average. The values are presented as means ± SE (*Compared with Water, P < 0.05). Abbreviations are the same as in legend Fig. 2 or otherwise indicated. A and B: chronic caffeine ingestion increased oxygen consumption in WT mice (Water: F, n = 8; M, n = 8; Caffeine: F, n = 7, M, n = 8). It also increased LA in male WT mice but not in female WT mice (Water: F, n = 7; M, n = 6; Caffeine: F, n = 9, M, n = 6). C and D: in A1RKO mice, chronic caffeine ingestion increased LA in both females and males (Water: F, n = 8; M, n = 8; Caffeine: F, n = 8, M, n = 8) but had no effect on O2C (Water: F, n = 7; M, n = 9; Caffeine: F, n = 9, M, n = 8). E and F: in A1-A2ARKO mice, chronic caffeine ingestion increased LA in males but not in females (Water: F, n = 8; M, n = 10; Caffeine: F, n = 8, M, n = 9). Chronic caffeine ingestion did not affect O2C (Water: F, n = 6; M, n = 7; Caffeine: F, n = 6, M, n = 7). G and H: in A2ARKO mice, chronic caffeine ingestion increased O2C in males but not in females (Water: F, n = 7; M, n = 6; Caffeine: F, n = 7, M, n = 4). LA was not affected in females or males (Water: F, n = 8; M, n = 10; Caffeine: F, n = 8, M, n = 8).