Figures & data
Notes: The cutaneous innervation of the sural nerve is located on the lateral side of the hindlimb. The test area (circled in red) is between the bony landmarks of the patella and tuber calcanei and within the areas of innervation of the lateral (shaded with dots) and caudal cutaneous (shaded with diagonal lines) sural nerves.
Notes: In pre-injury sheep, withdrawal thresholds were determined 1–2 weeks prior to surgery (n = 6). There was no significant difference between ipsilateral and contralateral hindlimbs. In sham sheep, withdrawal thresholds of ipsilateral and contralateral sham hindlimbs, determined 3 weeks after sham surgery, were not significantly different (n = 3). Furthermore, there was no significant difference between sham and pre-injury sheep. In nerve injured sheep, withdrawal thresholds of ipsilateral and contralateral hindlimbs were measured 3 weeks after PNI surgery (n = 6). Data were analyzed using one-way ANOVA followed by Bonferroni correction. The ipsilateral nerve injured hindlimb showed a markedly reduced threshold (9.6 ± 1.7 g, n = 6); *P < 0.0001. The withdrawal threshold of the contralateral hindlimb was not significantly different from sham or pre-injury sheep.
Abbreviations: ANOVA, analysis of variance; PNI, peroneal nerve injury.
Abbreviations: ANOVA, analysis of variance; PNI, peroneal nerve injury.
Notes: Withdrawal thresholds of the ipsilateral hindlimb of sham sheep were not significantly different from those of the contralateral hindlimb and remained unchanged for the duration of the study. Comparison of withdrawal thresholds among sheep groups was analyzed by mixed ANOVA. *Significant difference (P < 0.001) from day 0. All of the experiments were repeated in six sheep.
Abbreviations: ANOVA, analysis of variance; PNI, peroneal nerve injury.
Abbreviations: ANOVA, analysis of variance; PNI, peroneal nerve injury.
Notes: The analgesia produced by a single dose of IT morphine was measured in pre-injury sheep (n = 3). A dose of morphine, eg, 50 μg/100 μL, was given at time 0. The withdrawal thresholds were measured at various intervals. The analgesia could be observed within 15 minutes of morphine application and reached a peak value after 30 minutes. The analgesia was maintained at the peak level for another 45 minutes before beginning to decrease at 75 minutes after morphine application. The morphine analgesic effect dissipated in 150–200 minutes. The level of peak analgesia was dose-dependent. Data were analyzed by one-way ANOVA repeated measures followed by post hoc test using the Bonferroni method. *Significant change from the withdrawal threshold measured prior to morphine injection.
Abbreviations: ANOVA, analysis of variance; IT, intrathecal.
Abbreviations: ANOVA, analysis of variance; IT, intrathecal.
Note: The ED50 was 76.3 μg for pre-injury, 65.5 μg for sham, and 159.0 μg for nerve-injured sheep. Some of the standard errors of the data ≤ symbol sizes.
Abbreviations: ED50, the IT morphine dose that produces 50% of maximal analgesia; IT, intrathecal; PNI, peroneal nerve injury.
Abbreviations: ED50, the IT morphine dose that produces 50% of maximal analgesia; IT, intrathecal; PNI, peroneal nerve injury.