Mean arterial pressure (MAP) over time with respect to intervention. Rats (n = 7 each group) were anesthetized with a 1.5% isoflurane–oxygen mixture. MAP was determined from the beginning (time = 0) of the 45-min infusion at predesignated intervals as described earlier under Materials and Methods. Groups include normal saline (NS) with or without furosemide (FUR), 25% mannitol (MAN), and 4.2% hypertonic saline (HS) with or without furosemide. MAP was allowed to fluctuate freely over the entire experiment. The mean value of MAP (99.3% CI, adjusted for multiple comparisons) over the course of the experiment is indicated in the inset of the figure. These means correspond to the value of the corresponding regression lines 2.25 h from the start of the experiment. The P value indicates the significance of differences when these are compared to the mannitol (Ref) group. The slope of the NS group was steeper than the mannitol group (P < 0.001), but the slopes of the other groups did not differ from mannitol (P 0.030). Although the initial values of MAP (time = 0) did differ between groups (P < 0.001), these differences did not appear to contribute to the observed values of MAP over the course of the experiment (P = 0.289).