The effects of NR2 subunit antagonists on the expression of p-p38 MAPK. Changes in the expression of p-p38 MAPK in medullary dorsal horn of rats with compression of the trigeminal of nerve root following the administration of NR2 subunit antagonists (n = 5 in each treatment group). The intracisternal administration of vehicle did not affect p-p38 MAPK levels caused by compression of the trigeminal nerve root (B). However, the intracisternal administration of AP5 (10 μg), PPPA (1 μg), or PPDA (5 μg) decreased p-p38 MAPK expression in the medullary dorsal horn (C-E). However, Ro25-6981 (100 μg) did not affect p-p38 MAPK levels (F). Western blot analyses further confirmed that the upregulation of p-p38 MAPK was significantly suppressed by all NR2 subunit antagonists tested except for Ro25-6981 (G, H). The total p38 (t-p38) levels were used as the loading control. Scale bar, 50 μm. #P < 0.05, compared with the sham-treated group, *P < 0.05, compared with the vehicle-treated group.