Figure 4.

Behavioral responses to acute pain, hindpaw injection of formalin in rats with gene transfer. The RVM 5-HT system is not required for acute pain responses to thermal (A) and mechanical (B) stimuli. Animal mobility is measured using the rotarod test. No difference between both groups is observed, ruling out a potential motor impair in descending 5-HT-deleted rats (C). The descending depletion of Tph-2 significantly attenuates of the spontaneous nocifensive responses in the second phase but not the first phase after unilateral hindpaw injection of formalin (D). **p < 0.01, Tph-2 shRNA versus control shRNA-treated group.