Figure 1

Mean (±SEM) changes in NAc and subcutaneous oxygen levels, temperature parameters, and locomotion induced by iv heroin delivered to awake, quietly resting rats at a low, self-administering dose (0.1 mg/kg). Left panels (A–D) show changes assessed with slow time-resolution (1-min bins) and right panels (E–G) show changes assessed at high temporal resolution (10-s bins). Values significantly different from baseline are shown as filled symbols; n indicates the number of averaged tests. Vertical dotted lines show the moment of iv heroin injection and horizontal dotted lines show baselines. H shows the correlation between oxygen changes in the NAc and subcutaneous space for the first 20 min from the onset of the injection. Red symbols show values where both parameters tightly correlated (red line is the regression line).