Mean rate of O2 consumption for a period of 2.5h following MK-801, icv [0.2μg (n=5), 2.0μg (n=4), 20μg (n=3) or 200μg (n=3) does not differ from mean rate of O2 consumption following saline injection (icv) (n=5)]. Insert shows that handling-induced arousal (HIA) (n=3) produces a significant increase in O2 consumption compared to MK-801 (200μg, icv) (*p<0.05, 2-way ANOVA with repeated measures).