Figure 3

Percent maximum possible effect of intrathecal morphine after injury in wild-type and e37b-only mice. Latency to paw withdrawal from thermal stimulus after intrathecal morphine injection (3 μg morphine sulfate) converted into percent maximum possible effect (MPE) using formula: (PWLmorphine - PWLbaseline) × 100/(20 - PWLbaseline) for each time point indicated. A, Comparison of spinal morphine effect in response to noxious thermal stimuli in WT mice measured from paws contralateral (WT-C) and ipsilateral (WT-I) to the site of injury. P values at 0, 10, 20, 30, 40, 50 and 60 min after morphine injection were 0.32, 0.001, 1.5 × 10^-5, 0.007, 0.4, 0.42 and 0.91. B, Area under the curve (AUC) of the %MPE was calculated for each ipsilateral and contralateral paw and measurements from the same animals connected by a line. There is a significant reduction in AUC for morphine analgesia in ipsilateral compared to contralateral measurements (P = 0.0174). C, Comparison of spinal morphine effect in response to noxious thermal stimuli in e37b-only mice measured from paws contralateral (37b-C) and ipsilateral (37b-I) to the site of injury. P values at 0, 10, 20, 30, 40, 50 and 60 min after morphine injection were 0.13, 0.76, 0.74, 0.44, 0.89, 0.66, 0.36. D, Area under the curve of the %MPE was calculated for ipsilateral and contralateral measurements, connecting lines show measurements within each animal. Average values and SE are shown (red symbols). There is no significant difference in AUC for morphine analgesia in ipsilateral compared to contralateral measurements (P = 0.777). (Student’s two-tailed t-test for all comparisons).