A series of representative images of the left and right paws while the central stump of cut L4 (1st and 2nd rows) and peripheral stump of cut L5 (3rd row) dorsal root was stimulated. The blue patches on the paw indicate plasma extravasation due to leakage of Evans Blue (EB). Note: A - before EB injection, B - after EB injection, C - 0.5 min, D - 2 min, E - 3.5 min, and F - 5 min after onset of stimulation. A summary shows the changes in color intensity (G) or changes in percentage of color intensity (H) of the ipsilateral (left) or contralateral (right) paws following electrical stimulation of either the central stump of L4 or the peripheral stump of the left L5 dorsal root. When the central stump of the left L4 dorsal root was stimulated, there were no significant differences in the color intensities (G) and percentage changes in color intensity (H) between the left (filled diamond) and right paws (open square). However, significant differences of color intensity and percentage change in color intensity were detected in the left paw when the central stump of L4 (filled diamond) and peripheral stump of L5 dorsal root (filled triangle) were stimulated. A summary of plasma extravasation induced by stimulating intact L5 dorsal root (I) shows significant plasma extravasation (as indicated by the decrease of color intensity, n = 3) 5 min after stimulation. The gray area indicates the duration of stimulation (5 min). *: p < 0.05, ***: p < 0.001, Fisher LSD test, as compared with the color intensity before electrical stimulation. +: p < 0.05, Fisher LSD test, as comparing the peripheral L5 stimulation (left paw) with the central L4 stimulation (left paw). AU: arbitrary unit; C: as a control before stimulation.