Antinociceptive effects of SB203580, a p38 MAPK inhibitor. Effects of SB203580 on mechanical allodynia in rats with trigeminal neuropathic pain produced by mal-positioned dental implants (A). The intracisternal administration of SB203580 (1 or 10 μg) inhibited mechanical allodynia on the ipsilateral (left) and contralateral side (right) on POD 3 in a dose-dependent manner. These anti-allodynic responses persisted for six hours and were recovered within 24 hours. On POD 21 however, SB203580 did not produce anti-nociceptive effects (lower panel). The intracisternal administration of SB203580 (10 μg) attenuated p38 MAPK activation on POD 3 following inferior alveolar nerve injury as compared to the vehicle group (B). Western blotting analysis showed decreases in p-p38 MAPK expression following the injection of SB203580 as compared to the vehicle treatment (C). *P < 0.001, vehicle- vs. SB203580-treated group. Scale bars, 50 μm.