Figure 4. Effect of heat exposure on abdominal temperature and locomotor activity in freely moving mice with indwelling telemeters of the four genotypes.

Mice were exposed to a hot environment (39°C) for 1 h while abdominal temperature and locomotor activity were continuously monitored by a telemetric system. Data are presented as mean ± SEM of orexin-knockout mice (ORX-KO, n= 5), orexin neuron-ablated mice (ORX-AB, n= 5) and their corresponding wild-type littermates (WT_KO, n= 4 and WT_AB, n= 4). Insets are the changes in the abdominal temperature and locomotor activity expressed as the AUC above the baseline calculated for 60 min of the heat exposure. *P < 0.05 compared with baseline values before heat exposure (Bonferroni's post hoc test). n.s., Not significant.