Rapid change in the mechanical nociception threshold induced by remifentanil treatment.

Traces show the time course of the threshold of eight consecutive measurements with 5 minute intervals. Time 0 indicates the subcutaneous injection of remifentanil (open circle) or saline (filled circle). A repeated measures two-way ANOVA with Bonferroni multiple comparison test indicated that the threshold significantly increased at 5 and 10 minutes after remifentanil injection (**** indicated p < 0.0001, * indicated p = 0.0252). Data are represented as mean ± SEM. n = 6 for each group.