Figure 9.

Bumetanide (Bume) administration decreases the expression of pJNK1/2/3 in vitro and in vivo. Changes in the expression of different MAPKs assessed by Western blot and ELISA. A–C, Representative blots and quantification of pJNK1/2/3, p38 MAPK, and pERK1/2 expression. Bumetanide administration prevented the increase of pJNK1/2/3 observed in injured animals (*p < 0.05, one-way ANOVA). Increased expression of pERK1/2 is also observed in injured animals compared with naive animals (*p < 0.05, +p < 0.05, one-way ANOVA). D, ELISA results showed increased expression of pERK1/2, p38, and pJNK1/2/3 in DRGs after nerve injury in vehicle-treated animals. Bumetanide administration reduced the expression of pERK1/2 (#p = 0.06) and pJNK1/2/3 (**p < 0.01) without affecting that of p38MAPK. E, DRG-dissociated cultures with the cell cycle inhibitor AraC were performed to isolate the effect of bumetanide administration on MAPK expression in neurons. Bumetanide administration decreased pJNK1/2/3 expression (*p < 0.05), but not pERK1/2 expression. F, G, Immunohistochemical localization of pERK1/2 also confirmed its expression in satellite cells surrounding DRG neurons (F), while JNK was expressed mainly in DRG neuron somas (G).