Sequential pain responses in the formalin test related to duration of treatment. The treatment occurred 5 minutes after pain induction. In all of the following figures, the response could not be measured from 5 minute to 10 minute. The black bar labeled "acupuncture" indicates the 5 minute time interval during which the 30 second, 1 minute, or 3 minute treatment occurred for all mice. All data are presented as mean ± SE. **p < 0.01 when compared to the control group. #p < 0.05 when compared to the Duration 1 group.