WDT, WDT and PPT.

Mean value and standard deviation of WDT and HPT are shown in this table, as well as median values and 25–75% IQR of PPT. On Day 2 and 4, pin-prick assessments were performed before and after i.v. administration of naloxone or placebo, whereas HPT and WDT were only assessed after drug infusion. Naloxone administration was not associated with changes in WDT (P = 0.39), HPT (P = 0.21) and PPT (P = 0.98). There were no significant differences in WDT and HPT, assessed in the BI-area, between Day 1 and 2 ([baseline vs. 73 hrs PB, Fig. 2] P = 0.10, P = 0.27, respectively), and between Day 3 and 4 (P = 0.13, P = 0.12, respectively). HPT = Heat pain thresholds, PPT = Pin-prick thresholds, WDT = Warmth detection thresholds.