Figure 2.

Plantar dynamic mechanical stimulation-induced changes of heart rate (ΔHR) and mean arterial pressure (ΔMAP), evoked by using a brush. A. Cardiovascular changes categorized by injury group, including control animals that had skin incision only, animals that became hyperalgesic after spinal nerve ligation (SNL) injury, and animals that did not develop hyperalgesia after SNL. Data are shown for measurements at baseline (BL, open bar) and on different days after surgery (shaded bars). On each day, measures for each animal are averaged across three repetitions (see Experimental Procedures). “n” indicates the number of animals in each group. B. Cardiovascular changes categorized by the type of motor behavior induced by stimulation, including no withdrawal (“None”), simple withdrawal, or sustained withdrawal accompanied by lifting, shaking and grooming (“Hyperalgesia”). Since only a single hyperalgesia event was evoked by brush stimulation, this was not included in the statistical analysis. Bars for each behavior include data pooled from different days (all except the BL day) and different injury groups. “n” indicates number of observations. “*” indicates a cardiovascular change significantly different from zero. P indicates probability for the main effect of behavior type. Bars in both panels indicate mean ± SEM. Note that the ordinate scales are the same in Figures 2 through 6.