To identify whether NOV could play a role during the development of inflammatory pain, we first performed a time-course analysis of NOV expression in the DRG and DHSC after either CFA or saline hind paw injection. From day 1 to 7 after pain induction, no significant variation of NOV mRNA expression was observed in the ipsilateral DRG and DHSC ( Figure 3A and 3B, and **data** not shown). By contrast, in the DRG, NOV mRNA levels were significantly decreased by 40% at day 15 (**P < 0.01, n = 6 to 8) and returned to their basal levels thereafter ( Figure 3A). Spinal NOV mRNA expression was significantly downregulated by 58% starting from day 15 post-CFA (**P < 0.01, n = 8) and persisted at low levels for at least 60 days with a 40% decrease (**P < 0.01, n = 6) ( Figure 3B). Consistent with the NOV mRNA expression pattern, NOV protein quantification on western blots in the ispilateral DHSC showed a significant (*P < 0.05, n = 5 to 6) decrease by 34%, 31% and 40% at 15, 21 and 60 days post-CFA, respectively ( Figure 3C). No variation of NOV distribution was observed in this structure in CFA rats compared to respective shams (data not shown). These results reveal the fact that, in the time course of CFA-induced pain, NOV levels are downregulated in the ipsilateral DRG and DHSC, suggesting a potential functional association between reduced NOV levels at a late phase and the establishment of prolonged pain.