Fig. 7.
Spinal nerve ligation activates spinal NR2B-bearing NMDAR or calmodulin-dependent protein kinase II signaling and downstream growth arrest and DNA-damage–inducible protein 45β (Gadd45β) to mediate behavioral allodynia. Image analysis demonstrated that, compared with sham operation (Sham 7D), spinal nerve ligation (SNL 7D) markedly increased phosphorylated NR2B-bearing N-methyl-d-aspartate receptor (pNR2B, red), phosphorylated calmodulin-dependent protein kinase II (pCaMKII, green), Gadd45β (blue), and pNR2B, pCaMKII, or Gadd45β triple-labeled (merge, white) immunofluorescence in the ipsilateral dorsal horn on day 7 postoperation, which were all reversed by spinal administration of Ro 25–6981 (SNL 7D + Ro 25–6981; a selective NR2B receptor antagonist; 100 nM, 10 μl; once daily on days 3 to 6 after SNL). KN-93 (SNL 7D + KN-93; a CaMKII antagonist; 50 nM; once daily on days 3 to 6 after SNL) reversed the SNL-increased pCaMKII, Gadd45β expression, and pNR2B, pCaMKII, or Gadd45β triple-labeled (white) without affecting the levels of pNR2B. Scale bar = 50 μm. Thickness = 50 μm. **P < 0.01 versus Sham 7D. ##P < 0.01 versus SNL 7D. n = 7. Data represent mean ± SD.