PPAR-α is differentially involved in the ligand-induced α7 nAChR-mediated antinociception in the formalin test. The α7 nAChR silent agonist NS6740 (9 mg/kg, i.p.), α7 nAChR positive allosteric modulator (PAM) PNU120596 (10 mg/kg, i.p.), and dual functional α7 nAChR allosteric agonist and PAM (ago-PAM) GAT107 (10 mg/kg, i.p.) evoked antinociceptive effects in formalin-injected mice in (A) phase I and (B) phase II, respectively. The PPAR-α antagonist GW6471 (2 mg/kg, i.p.) was not able to block their antinociceptive effects in both (A) phase I and (B) phase II. Data reflect the mean ± S.E.M. of 6 animals for each group. * P < 0.05, significantly different from its vehicle group.